diff mbox series

[v3,2/2] posix: Deprecate group_member for Linux

Message ID 20231013194452.2165882-3-josimmon@redhat.com
State Superseded
Headers
Series posix: Add group_member2 and deprecate group_member |

Checks

Context Check Description
redhat-pt-bot/TryBot-apply_patch success Patch applied to master at the time it was sent
redhat-pt-bot/TryBot-32bit success Build for i686
linaro-tcwg-bot/tcwg_glibc_check--master-aarch64 success Testing passed
linaro-tcwg-bot/tcwg_glibc_build--master-arm success Testing passed
linaro-tcwg-bot/tcwg_glibc_build--master-aarch64 success Testing passed
linaro-tcwg-bot/tcwg_glibc_check--master-arm success Testing passed

Commit Message

Joe Simmons-Talbott Oct. 13, 2023, 7:44 p.m. UTC 
  The alloca usage in group_member could lead to stack overflow on Linux.
Removing the alloca usage would require group_member to handle the error
condition where memory could not be allocated and that cannot be done
since group_member returns either 1 or 0 for found or not found
respectively.  Thus deprecate group_member.  Add a testcase.
---
Changes since v2:
* Add summary to both group_member.h files
* Move group_member.h to bits/group_member.h and ensure it can only be
  included from unistd.h

 NEWS                                   |  4 ++-
 bits/group_member.h                    | 35 ++++++++++++++++++++++
 posix/Makefile                         |  4 +++
 posix/tst-group_member.c               | 41 ++++++++++++++++++++++++++
 posix/unistd.h                         |  9 ++----
 sysdeps/unix/sysv/linux/group_member.h | 36 ++++++++++++++++++++++
 6 files changed, 122 insertions(+), 7 deletions(-)
 create mode 100644 bits/group_member.h
 create mode 100644 posix/tst-group_member.c
 create mode 100644 sysdeps/unix/sysv/linux/group_member.h
diff mbox series

Patch

diff --git a/NEWS b/NEWS
index c15b0dd0f9..0cfaf9c80a 100644
--- a/NEWS
+++ b/NEWS
@@ -43,7 +43,9 @@  Major new features:
 
 Deprecated and removed features, and other changes affecting compatibility:
 
-  [Add deprecations, removals and changes affecting compatibility here]
+* Deprecated group_member on Linux as it uses alloca to allocate a large
+  buffer and has no capability for indicating failure for other memory
+  allocations.
 
 Changes to build and runtime requirements:
 
diff --git a/bits/group_member.h b/bits/group_member.h
new file mode 100644
index 0000000000..a0e60da5f6
--- /dev/null
+++ b/bits/group_member.h
@@ -0,0 +1,35 @@ 
+/* group_member and group_member2 declarations
+  
+   Copyright (C) 2023 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _UNISTD_H
+# error "Never use <bits/group_member.h> directly; include <unistd.h> instead."
+#endif
+
+#ifndef _GROUP_MEMBER_H
+#define _GROUP_MEMBER_H 1
+
+#ifdef	__USE_GNU
+/* Return nonzero iff the calling process is in group GID.  */
+extern int group_member (__gid_t __gid) __THROW;
+/* Return nonzero iff the calling process is in group GID.  Return
+   -1 on error and set errno.  */
+extern int group_member2 (__gid_t __gid) __THROW;
+#endif
+
+#endif /* GROUP_MEMBER_H */
diff --git a/posix/Makefile b/posix/Makefile
index b46ff3259c..13fd2843a3 100644
--- a/posix/Makefile
+++ b/posix/Makefile
@@ -29,6 +29,7 @@  headers := \
   bits/getopt_core.h \
   bits/getopt_ext.h \
   bits/getopt_posix.h \
+  bits/group_member.h \
   bits/local_lim.h \
   bits/mman_ext.h \
   bits/posix1_lim.h \
@@ -294,6 +295,7 @@  tests := \
   tst-glob_symlinks \
   tst-gnuglob \
   tst-gnuglob64 \
+  tst-group_member \
   tst-group_member2 \
   tst-mmap \
   tst-mmap-offset \
@@ -616,6 +618,8 @@  bug-glob1-ARGS = "$(objpfx)"
 tst-execvp3-ARGS = --test-dir=$(objpfx)
 CFLAGS-tst-spawn3.c += -DOBJPFX=\"$(objpfx)\"
 
+CFLAGS-tst-group_member.c += -Wno-error=deprecated-declarations
+
 # Test voluntarily overflows struct dirent
 CFLAGS-bug-glob2.c += $(no-fortify-source)
 
diff --git a/posix/tst-group_member.c b/posix/tst-group_member.c
new file mode 100644
index 0000000000..7f70841832
--- /dev/null
+++ b/posix/tst-group_member.c
@@ -0,0 +1,41 @@ 
+/* Basic tests for group_member.
+   Copyright (C) 2023 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <alloca.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include <support/check.h>
+
+static int do_test (void)
+{
+  int n;
+  gid_t *groups;
+
+  n = getgroups (0, NULL);
+  groups = alloca (n * sizeof (*groups));
+  n = getgroups (n, groups);
+
+  while (n-- > 0)
+    TEST_COMPARE (1, group_member(groups[n]));
+
+  return EXIT_SUCCESS;
+}
+
+#include <support/test-driver.c>
diff --git a/posix/unistd.h b/posix/unistd.h
index 96816b186d..b65d4c63d0 100644
--- a/posix/unistd.h
+++ b/posix/unistd.h
@@ -710,13 +710,10 @@  extern __gid_t getegid (void) __THROW;
    of its supplementary groups in LIST and return the number written.  */
 extern int getgroups (int __size, __gid_t __list[]) __THROW __wur
     __fortified_attr_access (__write_only__, 2, 1);
+
 #ifdef	__USE_GNU
-/* Return nonzero iff the calling process is in group GID.  */
-extern int group_member (__gid_t __gid) __THROW;
-/* Return nonzero iff the calling process is in group GID.  Return
-   -1 on error and set errno.  */
-extern int group_member2 (__gid_t __gid) __THROW;
-#endif
+# include <bits/group_member.h>
+#endif 
 
 /* Set the user ID of the calling process to UID.
    If the calling process is the super-user, set the real
diff --git a/sysdeps/unix/sysv/linux/group_member.h b/sysdeps/unix/sysv/linux/group_member.h
new file mode 100644
index 0000000000..7d6858e069
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/group_member.h
@@ -0,0 +1,36 @@ 
+/* group_member and group_member2 declarations
+  
+   Copyright (C) 2023 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _UNISTD_H
+# error "Never use <bits/group_member.h> directly; include <unistd.h> instead."
+#endif
+
+#ifndef _GROUP_MEMBER_H
+#define _GROUP_MEMBER_H 1
+
+#ifdef	__USE_GNU
+/* Return nonzero iff the calling process is in group GID.  Deprecated */
+extern int group_member (__gid_t __gid) __THROW
+	__attribute_deprecated_msg__ ("may overflow the stack");
+/* Return nonzero iff the calling process is in group GID.  Return
+   -1 on error and set errno.  */
+extern int group_member2 (__gid_t __gid) __THROW;
+#endif
+
+#endif /* GROUP_MEMBER_H */