@@ -68,6 +68,9 @@ along with GCC; see the file COPYING3. If not see
#include "plugin.h"
#include "target.h"
#include <memory>
+#include "stringpool.h"
+#include "attribs.h"
+#include "tree-dfa.h"
/* For an overview, see gcc/doc/analyzer.texi. */
@@ -2287,6 +2290,116 @@ exploded_graph::~exploded_graph ()
delete (*iter).second;
}
+/* Subroutine for use when implementing __attribute__((tainted_args))
+ on functions and on function pointer fields in structs.
+
+ Called on STATE representing a call to FNDECL.
+ Mark all params of FNDECL in STATE as "tainted". Mark the value of all
+ regions pointed to by params of FNDECL as "tainted".
+
+ Return true if successful; return false if the "taint" state machine
+ was not found. */
+
+static bool
+mark_params_as_tainted (program_state *state, tree fndecl,
+ const extrinsic_state &ext_state)
+{
+ unsigned taint_sm_idx;
+ if (!ext_state.get_sm_idx_by_name ("taint", &taint_sm_idx))
+ return false;
+ sm_state_map *smap = state->m_checker_states[taint_sm_idx];
+
+ const state_machine &sm = ext_state.get_sm (taint_sm_idx);
+ state_machine::state_t tainted = sm.get_state_by_name ("tainted");
+
+ region_model_manager *mgr = ext_state.get_model_manager ();
+
+ function *fun = DECL_STRUCT_FUNCTION (fndecl);
+ gcc_assert (fun);
+
+ for (tree iter_parm = DECL_ARGUMENTS (fndecl); iter_parm;
+ iter_parm = DECL_CHAIN (iter_parm))
+ {
+ tree param = iter_parm;
+ if (tree parm_default_ssa = ssa_default_def (fun, iter_parm))
+ param = parm_default_ssa;
+ const region *param_reg = state->m_region_model->get_lvalue (param, NULL);
+ const svalue *init_sval = mgr->get_or_create_initial_value (param_reg);
+ smap->set_state (state->m_region_model, init_sval,
+ tainted, NULL /*origin_new_sval*/, ext_state);
+ if (POINTER_TYPE_P (TREE_TYPE (param)))
+ {
+ const region *pointee_reg = mgr->get_symbolic_region (init_sval);
+ /* Mark "*param" as tainted. */
+ const svalue *init_pointee_sval
+ = mgr->get_or_create_initial_value (pointee_reg);
+ smap->set_state (state->m_region_model, init_pointee_sval,
+ tainted, NULL /*origin_new_sval*/, ext_state);
+ }
+ }
+
+ return true;
+}
+
+/* Custom event for use by tainted_args_function_info when a function
+ has been marked with __attribute__((tainted_args)). */
+
+class tainted_args_function_custom_event : public custom_event
+{
+public:
+ tainted_args_function_custom_event (location_t loc, tree fndecl, int depth)
+ : custom_event (loc, fndecl, depth),
+ m_fndecl (fndecl)
+ {
+ }
+
+ label_text get_desc (bool can_colorize) const FINAL OVERRIDE
+ {
+ return make_label_text
+ (can_colorize,
+ "function %qE marked with %<__attribute__((tainted_args))%>",
+ m_fndecl);
+ }
+
+private:
+ tree m_fndecl;
+};
+
+/* Custom exploded_edge info for top-level calls to a function
+ marked with __attribute__((tainted_args)). */
+
+class tainted_args_function_info : public custom_edge_info
+{
+public:
+ tainted_args_function_info (tree fndecl)
+ : m_fndecl (fndecl)
+ {}
+
+ void print (pretty_printer *pp) const FINAL OVERRIDE
+ {
+ pp_string (pp, "call to tainted_args function");
+ };
+
+ bool update_model (region_model *,
+ const exploded_edge *,
+ region_model_context *) const FINAL OVERRIDE
+ {
+ /* No-op. */
+ return true;
+ }
+
+ void add_events_to_path (checker_path *emission_path,
+ const exploded_edge &) const FINAL OVERRIDE
+ {
+ emission_path->add_event
+ (new tainted_args_function_custom_event
+ (DECL_SOURCE_LOCATION (m_fndecl), m_fndecl, 0));
+ }
+
+private:
+ tree m_fndecl;
+};
+
/* Ensure that there is an exploded_node representing an external call to
FUN, adding it to the worklist if creating it.
@@ -2313,14 +2426,25 @@ exploded_graph::add_function_entry (function *fun)
program_state state (m_ext_state);
state.push_frame (m_ext_state, fun);
+ custom_edge_info *edge_info = NULL;
+
+ if (lookup_attribute ("tainted_args", DECL_ATTRIBUTES (fun->decl)))
+ {
+ if (mark_params_as_tainted (&state, fun->decl, m_ext_state))
+ edge_info = new tainted_args_function_info (fun->decl);
+ }
+
if (!state.m_valid)
return NULL;
exploded_node *enode = get_or_create_node (point, state, NULL);
if (!enode)
- return NULL;
+ {
+ delete edge_info;
+ return NULL;
+ }
- add_edge (m_origin, enode, NULL);
+ add_edge (m_origin, enode, NULL, edge_info);
m_functions_with_enodes.add (fun);
@@ -2634,6 +2758,187 @@ toplevel_function_p (function *fun, logger *logger)
return true;
}
+/* Custom event for use by tainted_call_info when a callback field has been
+ marked with __attribute__((tainted_args)), for labelling the field. */
+
+class tainted_args_field_custom_event : public custom_event
+{
+public:
+ tainted_args_field_custom_event (tree field)
+ : custom_event (DECL_SOURCE_LOCATION (field), NULL_TREE, 0),
+ m_field (field)
+ {
+ }
+
+ label_text get_desc (bool can_colorize) const FINAL OVERRIDE
+ {
+ return make_label_text (can_colorize,
+ "field %qE of %qT"
+ " is marked with %<__attribute__((tainted_args))%>",
+ m_field, DECL_CONTEXT (m_field));
+ }
+
+private:
+ tree m_field;
+};
+
+/* Custom event for use by tainted_call_info when a callback field has been
+ marked with __attribute__((tainted_args)), for labelling the function used
+ in that callback. */
+
+class tainted_args_callback_custom_event : public custom_event
+{
+public:
+ tainted_args_callback_custom_event (location_t loc, tree fndecl, int depth,
+ tree field)
+ : custom_event (loc, fndecl, depth),
+ m_field (field)
+ {
+ }
+
+ label_text get_desc (bool can_colorize) const FINAL OVERRIDE
+ {
+ return make_label_text (can_colorize,
+ "function %qE used as initializer for field %qE"
+ " marked with %<__attribute__((tainted_args))%>",
+ m_fndecl, m_field);
+ }
+
+private:
+ tree m_field;
+};
+
+/* Custom edge info for use when adding a function used by a callback field
+ marked with '__attribute__((tainted_args))'. */
+
+class tainted_args_call_info : public custom_edge_info
+{
+public:
+ tainted_args_call_info (tree field, tree fndecl, location_t loc)
+ : m_field (field), m_fndecl (fndecl), m_loc (loc)
+ {}
+
+ void print (pretty_printer *pp) const FINAL OVERRIDE
+ {
+ pp_string (pp, "call to tainted field");
+ };
+
+ bool update_model (region_model *,
+ const exploded_edge *,
+ region_model_context *) const FINAL OVERRIDE
+ {
+ /* No-op. */
+ return true;
+ }
+
+ void add_events_to_path (checker_path *emission_path,
+ const exploded_edge &) const FINAL OVERRIDE
+ {
+ /* Show the field in the struct declaration, e.g.
+ "(1) field 'store' is marked with '__attribute__((tainted_args))'" */
+ emission_path->add_event
+ (new tainted_args_field_custom_event (m_field));
+
+ /* Show the callback in the initializer
+ e.g.
+ "(2) function 'gadget_dev_desc_UDC_store' used as initializer
+ for field 'store' marked with '__attribute__((tainted_args))'". */
+ emission_path->add_event
+ (new tainted_args_callback_custom_event (m_loc, m_fndecl, 0, m_field));
+ }
+
+private:
+ tree m_field;
+ tree m_fndecl;
+ location_t m_loc;
+};
+
+/* Given an initializer at LOC for FIELD marked with
+ '__attribute__((tainted_args))' initialized with FNDECL, add an
+ entrypoint to FNDECL to EG (and to its worklist) where the params to
+ FNDECL are marked as tainted. */
+
+static void
+add_tainted_args_callback (exploded_graph *eg, tree field, tree fndecl,
+ location_t loc)
+{
+ logger *logger = eg->get_logger ();
+
+ LOG_SCOPE (logger);
+
+ if (!gimple_has_body_p (fndecl))
+ return;
+
+ const extrinsic_state &ext_state = eg->get_ext_state ();
+
+ function *fun = DECL_STRUCT_FUNCTION (fndecl);
+ gcc_assert (fun);
+
+ program_point point
+ = program_point::from_function_entry (eg->get_supergraph (), fun);
+ program_state state (ext_state);
+ state.push_frame (ext_state, fun);
+
+ if (!mark_params_as_tainted (&state, fndecl, ext_state))
+ return;
+
+ if (!state.m_valid)
+ return;
+
+ exploded_node *enode = eg->get_or_create_node (point, state, NULL);
+ if (logger)
+ {
+ if (enode)
+ logger->log ("created EN %i for tainted_args %qE entrypoint",
+ enode->m_index, fndecl);
+ else
+ {
+ logger->log ("did not create enode for tainted_args %qE entrypoint",
+ fndecl);
+ return;
+ }
+ }
+
+ tainted_args_call_info *info
+ = new tainted_args_call_info (field, fndecl, loc);
+ eg->add_edge (eg->get_origin (), enode, NULL, info);
+}
+
+/* Callback for walk_tree for finding callbacks within initializers;
+ ensure that any callback initializer where the corresponding field is
+ marked with '__attribute__((tainted_args))' is treated as an entrypoint
+ to the analysis, special-casing that the inputs to the callback are
+ untrustworthy. */
+
+static tree
+add_any_callbacks (tree *tp, int *, void *data)
+{
+ exploded_graph *eg = (exploded_graph *)data;
+ if (TREE_CODE (*tp) == CONSTRUCTOR)
+ {
+ /* Find fields with the "tainted_args" attribute.
+ walk_tree only walks the values, not the index values;
+ look at the index values. */
+ unsigned HOST_WIDE_INT idx;
+ constructor_elt *ce;
+
+ for (idx = 0; vec_safe_iterate (CONSTRUCTOR_ELTS (*tp), idx, &ce);
+ idx++)
+ if (ce->index && TREE_CODE (ce->index) == FIELD_DECL)
+ if (lookup_attribute ("tainted_args", DECL_ATTRIBUTES (ce->index)))
+ {
+ tree value = ce->value;
+ if (TREE_CODE (value) == ADDR_EXPR
+ && TREE_CODE (TREE_OPERAND (value, 0)) == FUNCTION_DECL)
+ add_tainted_args_callback (eg, ce->index,
+ TREE_OPERAND (value, 0),
+ EXPR_LOCATION (value));
+ }
+ }
+
+ return NULL_TREE;
+}
+
/* Add initial nodes to EG, with entrypoints for externally-callable
functions. */
@@ -2659,6 +2964,17 @@ exploded_graph::build_initial_worklist ()
logger->log ("did not create enode for %qE entrypoint", fun->decl);
}
}
+
+ /* Find callbacks that are reachable from global initializers. */
+ varpool_node *vpnode;
+ FOR_EACH_VARIABLE (vpnode)
+ {
+ tree decl = vpnode->decl;
+ tree init = DECL_INITIAL (decl);
+ if (!init)
+ continue;
+ walk_tree (&init, add_any_callbacks, this, NULL);
+ }
}
/* The main loop of the analysis.
@@ -117,6 +117,7 @@ static tree handle_no_profile_instrument_function_attribute (tree *, tree,
tree, int, bool *);
static tree handle_malloc_attribute (tree *, tree, tree, int, bool *);
static tree handle_dealloc_attribute (tree *, tree, tree, int, bool *);
+static tree handle_tainted_args_attribute (tree *, tree, tree, int, bool *);
static tree handle_returns_twice_attribute (tree *, tree, tree, int, bool *);
static tree handle_no_limit_stack_attribute (tree *, tree, tree, int,
bool *);
@@ -548,6 +549,8 @@ const struct attribute_spec c_common_attribute_table[] =
handle_objc_nullability_attribute, NULL },
{ "*dealloc", 1, 2, true, false, false, false,
handle_dealloc_attribute, NULL },
+ { "tainted_args", 0, 0, true, false, false, false,
+ handle_tainted_args_attribute, NULL },
{ NULL, 0, 0, false, false, false, false, NULL, NULL }
};
@@ -5774,6 +5777,39 @@ handle_objc_nullability_attribute (tree *node, tree name, tree args,
return NULL_TREE;
}
+/* Handle a "tainted_args" attribute; arguments as in
+ struct attribute_spec.handler. */
+
+static tree
+handle_tainted_args_attribute (tree *node, tree name, tree, int,
+ bool *no_add_attrs)
+{
+ if (TREE_CODE (*node) != FUNCTION_DECL
+ && TREE_CODE (*node) != FIELD_DECL)
+ {
+ warning (OPT_Wattributes, "%qE attribute ignored; valid only "
+ "for functions and function pointer fields",
+ name);
+ *no_add_attrs = true;
+ return NULL_TREE;
+ }
+
+ if (TREE_CODE (*node) == FIELD_DECL
+ && !(TREE_CODE (TREE_TYPE (*node)) == POINTER_TYPE
+ && TREE_CODE (TREE_TYPE (TREE_TYPE (*node))) == FUNCTION_TYPE))
+ {
+ warning (OPT_Wattributes, "%qE attribute ignored;"
+ " field must be a function pointer",
+ name);
+ *no_add_attrs = true;
+ return NULL_TREE;
+ }
+
+ *no_add_attrs = false; /* OK */
+
+ return NULL_TREE;
+}
+
/* Attempt to partially validate a single attribute ATTR as if
it were to be applied to an entity OPER. */
@@ -2512,7 +2512,8 @@ variable declarations (@pxref{Variable Attributes}),
labels (@pxref{Label Attributes}),
enumerators (@pxref{Enumerator Attributes}),
statements (@pxref{Statement Attributes}),
-and types (@pxref{Type Attributes}).
+types (@pxref{Type Attributes}),
+and on field declarations (for @code{tainted_args}).
There is some overlap between the purposes of attributes and pragmas
(@pxref{Pragmas,,Pragmas Accepted by GCC}). It has been
@@ -4009,6 +4010,26 @@ addition to creating a symbol version (as if
@code{"@var{name2}@@@var{nodename}"} was used) the version will be also used
to resolve @var{name2} by the linker.
+@item tainted_args
+@cindex @code{tainted_args} function attribute
+The @code{tainted_args} attribute is used to specify that a function is called
+in a way that requires sanitization of its arguments, such as a system
+call in an operating system kernel. Such a function can be considered part
+of the ``attack surface'' of the program. The attribute can be used both
+on function declarations, and on field declarations containing function
+pointers. In the latter case, any function used as an initializer of
+such a callback field will be treated as being called with tainted
+arguments.
+
+The analyzer will pay particular attention to such functions when both
+@option{-fanalyzer} and @option{-fanalyzer-checker=taint} are supplied,
+potentially issuing warnings guarded by
+@option{-Wanalyzer-tainted-allocation-size},
+@option{-Wanalyzer-tainted-array-index},
+@option{-Wanalyzer-tainted-divisor},
+@option{-Wanalyzer-tainted-offset},
+and @option{-Wanalyzer-tainted-size}.
+
@item target_clones (@var{options})
@cindex @code{target_clones} function attribute
The @code{target_clones} attribute is used to specify that a function
new file mode 100644
@@ -0,0 +1,88 @@
+// TODO: remove need for this option
+/* { dg-additional-options "-fanalyzer-checker=taint" } */
+
+#include "analyzer-decls.h"
+
+struct arg_buf
+{
+ int i;
+ int j;
+};
+
+/* Example of marking a function as tainted. */
+
+void __attribute__((tainted_args))
+test_1 (int i, void *p, char *q)
+{
+ /* There should be a single enode,
+ for the "tainted" entry to the function. */
+ __analyzer_dump_exploded_nodes (0); /* { dg-warning "1 processed enode" } */
+
+ __analyzer_dump_state ("taint", i); /* { dg-warning "state: 'tainted'" } */
+ __analyzer_dump_state ("taint", p); /* { dg-warning "state: 'tainted'" } */
+ __analyzer_dump_state ("taint", q); /* { dg-warning "state: 'tainted'" } */
+ __analyzer_dump_state ("taint", *q); /* { dg-warning "state: 'tainted'" } */
+
+ struct arg_buf *args = p;
+ __analyzer_dump_state ("taint", args->i); /* { dg-warning "state: 'tainted'" } */
+ __analyzer_dump_state ("taint", args->j); /* { dg-warning "state: 'tainted'" } */
+}
+
+/* Example of marking a callback field as tainted. */
+
+struct s2
+{
+ void (*cb) (int, void *, char *)
+ __attribute__((tainted_args));
+};
+
+/* Function not marked as tainted. */
+
+void
+test_2a (int i, void *p, char *q)
+{
+ /* There should be a single enode,
+ for the normal entry to the function. */
+ __analyzer_dump_exploded_nodes (0); /* { dg-warning "1 processed enode" } */
+
+ __analyzer_dump_state ("taint", i); /* { dg-warning "state: 'start'" } */
+ __analyzer_dump_state ("taint", p); /* { dg-warning "state: 'start'" } */
+ __analyzer_dump_state ("taint", q); /* { dg-warning "state: 'start'" } */
+
+ struct arg_buf *args = p;
+ __analyzer_dump_state ("taint", args->i); /* { dg-warning "state: 'start'" } */
+ __analyzer_dump_state ("taint", args->j); /* { dg-warning "state: 'start'" } */
+}
+
+/* Function referenced via t2b.cb, marked as "tainted". */
+
+void
+test_2b (int i, void *p, char *q)
+{
+ /* There should be two enodes
+ for the direct call, and the "tainted" entry to the function. */
+ __analyzer_dump_exploded_nodes (0); /* { dg-warning "2 processed enodes" } */
+}
+
+/* Callback used via t2c.cb, marked as "tainted". */
+void
+__analyzer_test_2c (int i, void *p, char *q)
+{
+ /* There should be a single enode,
+ for the "tainted" entry to the function. */
+ __analyzer_dump_exploded_nodes (0); /* { dg-warning "1 processed enode" } */
+
+ __analyzer_dump_state ("taint", i); /* { dg-warning "state: 'tainted'" } */
+ __analyzer_dump_state ("taint", p); /* { dg-warning "state: 'tainted'" } */
+ __analyzer_dump_state ("taint", q); /* { dg-warning "state: 'tainted'" } */
+}
+
+struct s2 t2b =
+{
+ .cb = test_2b
+};
+
+struct s2 t2c =
+{
+ .cb = __analyzer_test_2c
+};
new file mode 100644
@@ -0,0 +1,6 @@
+int not_a_fn __attribute__ ((tainted_args)); /* { dg-warning "'tainted_args' attribute ignored; valid only for functions and function pointer fields" } */
+
+struct s
+{
+ int f __attribute__ ((tainted_args)); /* { dg-warning "'tainted_args' attribute ignored; field must be a function pointer" } */
+};
new file mode 100644
@@ -0,0 +1,93 @@
+/* "The osf_getsysinfo function in arch/alpha/kernel/osf_sys.c in the
+ Linux kernel before 2.6.39.4 on the Alpha platform does not properly
+ restrict the data size for GSI_GET_HWRPB operations, which allows
+ local users to obtain sensitive information from kernel memory via
+ a crafted call."
+
+ Fixed in 3d0475119d8722798db5e88f26493f6547a4bb5b on linux-2.6.39.y
+ in linux-stable. */
+
+// TODO: remove need for this option:
+/* { dg-additional-options "-fanalyzer-checker=taint" } */
+
+#include "analyzer-decls.h"
+#include "test-uaccess.h"
+
+/* Adapted from include/linux/linkage.h. */
+
+#define asmlinkage
+
+/* Adapted from include/linux/syscalls.h. */
+
+#define __SC_DECL1(t1, a1) t1 a1
+#define __SC_DECL2(t2, a2, ...) t2 a2, __SC_DECL1(__VA_ARGS__)
+#define __SC_DECL3(t3, a3, ...) t3 a3, __SC_DECL2(__VA_ARGS__)
+#define __SC_DECL4(t4, a4, ...) t4 a4, __SC_DECL3(__VA_ARGS__)
+#define __SC_DECL5(t5, a5, ...) t5 a5, __SC_DECL4(__VA_ARGS__)
+#define __SC_DECL6(t6, a6, ...) t6 a6, __SC_DECL5(__VA_ARGS__)
+
+#define SYSCALL_DEFINEx(x, sname, ...) \
+ __SYSCALL_DEFINEx(x, sname, __VA_ARGS__)
+
+#define SYSCALL_DEFINE(name) asmlinkage long sys_##name
+#define __SYSCALL_DEFINEx(x, name, ...) \
+ asmlinkage __attribute__((tainted_args)) \
+ long sys##name(__SC_DECL##x(__VA_ARGS__))
+
+#define SYSCALL_DEFINE5(name, ...) SYSCALL_DEFINEx(5, _##name, __VA_ARGS__)
+
+/* Adapted from arch/alpha/include/asm/hwrpb.h. */
+
+struct hwrpb_struct {
+ unsigned long phys_addr; /* check: physical address of the hwrpb */
+ unsigned long id; /* check: "HWRPB\0\0\0" */
+ unsigned long revision;
+ unsigned long size; /* size of hwrpb */
+ /* [...snip...] */
+};
+
+extern struct hwrpb_struct *hwrpb;
+
+/* Adapted from arch/alpha/kernel/osf_sys.c. */
+
+SYSCALL_DEFINE5(osf_getsysinfo, unsigned long, op, void __user *, buffer,
+ unsigned long, nbytes, int __user *, start, void __user *, arg)
+{
+ /* [...snip...] */
+
+ __analyzer_dump_state ("taint", nbytes); /* { dg-warning "tainted" } */
+
+ /* TODO: should have an event explaining why "nbytes" is treated as
+ attacker-controlled. */
+
+ /* case GSI_GET_HWRPB: */
+ if (nbytes < sizeof(*hwrpb))
+ return -1;
+
+ __analyzer_dump_state ("taint", nbytes); /* { dg-warning "has_lb" } */
+
+ if (copy_to_user(buffer, hwrpb, nbytes) != 0) /* { dg-warning "use of attacker-controlled value 'nbytes' as size without upper-bounds checking" } */
+ return -2;
+
+ return 1;
+
+ /* [...snip...] */
+}
+
+/* With the fix for the sense of the size comparison. */
+
+SYSCALL_DEFINE5(osf_getsysinfo_fixed, unsigned long, op, void __user *, buffer,
+ unsigned long, nbytes, int __user *, start, void __user *, arg)
+{
+ /* [...snip...] */
+
+ /* case GSI_GET_HWRPB: */
+ if (nbytes > sizeof(*hwrpb))
+ return -1;
+ if (copy_to_user(buffer, hwrpb, nbytes) != 0) /* { dg-bogus "attacker-controlled" } */
+ return -2;
+
+ return 1;
+
+ /* [...snip...] */
+}
new file mode 100644
@@ -0,0 +1,38 @@
+/* See notes in this header. */
+#include "taint-CVE-2020-13143.h"
+
+// TODO: remove need for this option
+/* { dg-additional-options "-fanalyzer-checker=taint" } */
+
+struct configfs_attribute {
+ /* [...snip...] */
+ ssize_t (*store)(struct config_item *, const char *, size_t) /* { dg-message "\\(1\\) field 'store' of 'struct configfs_attribute' is marked with '__attribute__\\(\\(tainted_args\\)\\)'" } */
+ __attribute__((tainted_args)); /* (this is added). */
+};
+static inline struct gadget_info *to_gadget_info(struct config_item *item)
+{
+ return container_of(to_config_group(item), struct gadget_info, group);
+}
+
+static ssize_t gadget_dev_desc_UDC_store(struct config_item *item,
+ const char *page, size_t len)
+{
+ struct gadget_info *gi = to_gadget_info(item);
+ char *name;
+ int ret;
+
+#if 0
+ /* FIXME: this is the fix. */
+ if (strlen(page) < len)
+ return -EOVERFLOW;
+#endif
+
+ name = kstrdup(page, GFP_KERNEL);
+ if (!name)
+ return -ENOMEM;
+ if (name[len - 1] == '\n') /* { dg-warning "use of attacker-controlled value 'len \[^\n\r\]+' as offset without upper-bounds checking" } */
+ name[len - 1] = '\0'; /* { dg-warning "use of attacker-controlled value 'len \[^\n\r\]+' as offset without upper-bounds checking" } */
+ /* [...snip...] */ \
+}
+
+CONFIGFS_ATTR(gadget_dev_desc_, UDC); /* { dg-message "\\(2\\) function 'gadget_dev_desc_UDC_store' used as initializer for field 'store' marked with '__attribute__\\(\\(tainted_args\\)\\)'" } */
new file mode 100644
@@ -0,0 +1,32 @@
+/* See notes in this header. */
+#include "taint-CVE-2020-13143.h"
+
+// TODO: remove need for this option
+/* { dg-additional-options "-fanalyzer-checker=taint" } */
+
+struct configfs_attribute {
+ /* [...snip...] */
+ ssize_t (*store)(struct config_item *, const char *, size_t) /* { dg-message "\\(1\\) field 'store' of 'struct configfs_attribute' is marked with '__attribute__\\(\\(tainted_args\\)\\)'" } */
+ __attribute__((tainted_args)); /* (this is added). */
+};
+
+/* Highly simplified version. */
+
+static ssize_t gadget_dev_desc_UDC_store(struct config_item *item,
+ const char *page, size_t len)
+{
+ /* TODO: ought to have state_change_event talking about where the tainted value comes from. */
+
+ char *name;
+ /* [...snip...] */
+
+ name = kstrdup(page, GFP_KERNEL);
+ if (!name)
+ return -ENOMEM;
+ if (name[len - 1] == '\n') /* { dg-warning "use of attacker-controlled value 'len \[^\n\r\]+' as offset without upper-bounds checking" } */
+ name[len - 1] = '\0'; /* { dg-warning "use of attacker-controlled value 'len \[^\n\r\]+' as offset without upper-bounds checking" } */
+ /* [...snip...] */
+ return 0;
+}
+
+CONFIGFS_ATTR(gadget_dev_desc_, UDC); /* { dg-message "\\(2\\) function 'gadget_dev_desc_UDC_store' used as initializer for field 'store' marked with '__attribute__\\(\\(tainted_args\\)\\)'" } */
new file mode 100644
@@ -0,0 +1,91 @@
+/* Shared header for the various taint-CVE-2020-13143.h tests.
+
+ "gadget_dev_desc_UDC_store in drivers/usb/gadget/configfs.c in the
+ Linux kernel 3.16 through 5.6.13 relies on kstrdup without considering
+ the possibility of an internal '\0' value, which allows attackers to
+ trigger an out-of-bounds read, aka CID-15753588bcd4."
+
+ Fixed by 15753588bcd4bbffae1cca33c8ced5722477fe1f on linux-5.7.y
+ in linux-stable. */
+
+// TODO: remove need for this option
+/* { dg-additional-options "-fanalyzer-checker=taint" } */
+
+#include <stddef.h>
+
+/* Adapted from include/uapi/asm-generic/posix_types.h */
+
+typedef unsigned int __kernel_size_t;
+typedef int __kernel_ssize_t;
+
+/* Adapted from include/linux/types.h */
+
+//typedef __kernel_size_t size_t;
+typedef __kernel_ssize_t ssize_t;
+
+/* Adapted from include/linux/kernel.h */
+
+#define container_of(ptr, type, member) ({ \
+ void *__mptr = (void *)(ptr); \
+ /* [...snip...] */ \
+ ((type *)(__mptr - offsetof(type, member))); })
+
+/* Adapted from include/linux/configfs.h */
+
+struct config_item {
+ /* [...snip...] */
+};
+
+struct config_group {
+ struct config_item cg_item;
+ /* [...snip...] */
+};
+
+static inline struct config_group *to_config_group(struct config_item *item)
+{
+ return item ? container_of(item,struct config_group,cg_item) : NULL;
+}
+
+#define CONFIGFS_ATTR(_pfx, _name) \
+static struct configfs_attribute _pfx##attr_##_name = { \
+ /* [...snip...] */ \
+ .store = _pfx##_name##_store, \
+}
+
+/* Adapted from include/linux/compiler.h */
+
+#define __force
+
+/* Adapted from include/asm-generic/errno-base.h */
+
+#define ENOMEM 12 /* Out of memory */
+
+/* Adapted from include/linux/types.h */
+
+#define __bitwise__
+typedef unsigned __bitwise__ gfp_t;
+
+/* Adapted from include/linux/gfp.h */
+
+#define ___GFP_WAIT 0x10u
+#define ___GFP_IO 0x40u
+#define ___GFP_FS 0x80u
+#define __GFP_WAIT ((__force gfp_t)___GFP_WAIT)
+#define __GFP_IO ((__force gfp_t)___GFP_IO)
+#define __GFP_FS ((__force gfp_t)___GFP_FS)
+#define GFP_KERNEL (__GFP_WAIT | __GFP_IO | __GFP_FS)
+
+/* Adapted from include/linux/compiler_attributes.h */
+
+#define __malloc __attribute__((__malloc__))
+
+/* Adapted from include/linux/string.h */
+
+extern char *kstrdup(const char *s, gfp_t gfp) __malloc;
+
+/* Adapted from drivers/usb/gadget/configfs.c */
+
+struct gadget_info {
+ struct config_group group;
+ /* [...snip...] */ \
+};
new file mode 100644
@@ -0,0 +1,21 @@
+// TODO: remove need for this option:
+/* { dg-additional-options "-fanalyzer-checker=taint" } */
+
+#include "analyzer-decls.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+/* malloc with tainted size from a syscall. */
+
+void *p;
+
+void __attribute__((tainted_args))
+test_1 (size_t sz) /* { dg-message "\\(1\\) function 'test_1' marked with '__attribute__\\(\\(tainted_args\\)\\)'" } */
+{
+ /* TODO: should have a message saying why "sz" is tainted, e.g.
+ "treating 'sz' as attacker-controlled because 'test_1' is marked with '__attribute__((tainted_args))'" */
+
+ p = malloc (sz); /* { dg-warning "use of attacker-controlled value 'sz' as allocation size without upper-bounds checking" "warning" } */
+ /* { dg-message "\\(\[0-9\]+\\) use of attacker-controlled value 'sz' as allocation size without upper-bounds checking" "final event" { target *-*-* } .-1 } */
+}
new file mode 100644
@@ -0,0 +1,31 @@
+// TODO: remove need for this option:
+/* { dg-additional-options "-fanalyzer-checker=taint" } */
+
+#include "analyzer-decls.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+/* malloc with tainted size from a syscall. */
+
+struct arg_buf
+{
+ size_t sz;
+};
+
+void *p;
+
+void __attribute__((tainted_args))
+test_1 (void *data) /* { dg-message "\\(1\\) function 'test_1' marked with '__attribute__\\(\\(tainted_args\\)\\)'" } */
+{
+ /* we should treat pointed-to-structs as tainted. */
+ __analyzer_dump_state ("taint", data); /* { dg-warning "state: 'tainted'" } */
+
+ struct arg_buf *args = data;
+
+ __analyzer_dump_state ("taint", args); /* { dg-warning "state: 'tainted'" } */
+ __analyzer_dump_state ("taint", args->sz); /* { dg-warning "state: 'tainted'" } */
+
+ p = malloc (args->sz); /* { dg-warning "use of attacker-controlled value '\\*args.sz' as allocation size without upper-bounds checking" "warning" } */
+ /* { dg-message "\\(\[0-9\]+\\) use of attacker-controlled value '\\*args.sz' as allocation size without upper-bounds checking" "final event" { target *-*-* } .-1 } */
+}
new file mode 100644
@@ -0,0 +1,15 @@
+/* Shared header for testcases for copy_from_user/copy_to_user. */
+
+/* Adapted from include/linux/compiler.h */
+
+#define __user
+
+/* Adapted from include/asm-generic/uaccess.h */
+
+extern int copy_from_user(void *to, const void __user *from, long n)
+ __attribute__((access (write_only, 1, 3),
+ access (read_only, 2, 3)));
+
+extern long copy_to_user(void __user *to, const void *from, unsigned long n)
+ __attribute__((access (write_only, 1, 3),
+ access (read_only, 2, 3)));