[v5] posix: Deprecate group_member for Linux

Message ID 20231020174235.1244927-1-josimmon@redhat.com
State Superseded
Headers
Series [v5] posix: Deprecate group_member for Linux |

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Commit Message

Joe Simmons-Talbott Oct. 20, 2023, 5:42 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 a boolean value.  Thus deprecate group_member.
Add a testcase.
---
Changes to v4:
* Rebase onto latest commit.

 NEWS                                        |  4 ++
 bits/group_member.h                         | 31 ++++++++++++++++
 posix/Makefile                              |  4 ++
 posix/tst-group_member.c                    | 41 +++++++++++++++++++++
 posix/unistd.h                              |  6 +--
 sysdeps/unix/sysv/linux/bits/group_member.h | 32 ++++++++++++++++
 6 files changed, 115 insertions(+), 3 deletions(-)
 create mode 100644 bits/group_member.h
 create mode 100644 posix/tst-group_member.c
 create mode 100644 sysdeps/unix/sysv/linux/bits/group_member.h
  

Comments

Joe Simmons-Talbott Oct. 30, 2023, 11:58 a.m. UTC | #1
Ping.

On Fri, Oct 20, 2023 at 01:42:31PM -0400, Joe Simmons-Talbott wrote:
> 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 a boolean value.  Thus deprecate group_member.
> Add a testcase.
> ---
> Changes to v4:
> * Rebase onto latest commit.
> 
>  NEWS                                        |  4 ++
>  bits/group_member.h                         | 31 ++++++++++++++++
>  posix/Makefile                              |  4 ++
>  posix/tst-group_member.c                    | 41 +++++++++++++++++++++
>  posix/unistd.h                              |  6 +--
>  sysdeps/unix/sysv/linux/bits/group_member.h | 32 ++++++++++++++++
>  6 files changed, 115 insertions(+), 3 deletions(-)
>  create mode 100644 bits/group_member.h
>  create mode 100644 posix/tst-group_member.c
>  create mode 100644 sysdeps/unix/sysv/linux/bits/group_member.h
> 
> diff --git a/NEWS b/NEWS
> index 9432564444..c1f9e5d0cc 100644
> --- a/NEWS
> +++ b/NEWS
> @@ -44,6 +44,10 @@ Deprecated and removed features, and other changes affecting compatibility:
>    ".tmp", to avoid examining temporary files created by the RPM and dpkg
>    package managers.
>  
> +* 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:
>  
>  * Building on LoongArch requires at a minimum binutils 2.41 for vector
> diff --git a/bits/group_member.h b/bits/group_member.h
> new file mode 100644
> index 0000000000..7c43e7ee06
> --- /dev/null
> +++ b/bits/group_member.h
> @@ -0,0 +1,31 @@
> +/* group_member declaration
> +   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 _BITS_GROUP_MEMBER_H
> +# define _BITS_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;
> +# endif
> +
> +#endif /* _BITS_GROUP_MEMBER_H */
> diff --git a/posix/Makefile b/posix/Makefile
> index c36b9d981e..d3e3c08fd1 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-mmap \
>    tst-mmap-offset \
>    tst-nanosleep \
> @@ -615,6 +617,8 @@ 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 0477527a60..b65d4c63d0 100644
> --- a/posix/unistd.h
> +++ b/posix/unistd.h
> @@ -710,10 +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;
> -#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/bits/group_member.h b/sysdeps/unix/sysv/linux/bits/group_member.h
> new file mode 100644
> index 0000000000..0dd9505c76
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/bits/group_member.h
> @@ -0,0 +1,32 @@
> +/* group_member declaration
> +   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 _BITS_GROUP_MEMBER_H
> +# define _BITS_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");
> +# endif
> +
> +#endif /* _BITS_GROUP_MEMBER_H */
> -- 
> 2.39.2
>
  

Patch

diff --git a/NEWS b/NEWS
index 9432564444..c1f9e5d0cc 100644
--- a/NEWS
+++ b/NEWS
@@ -44,6 +44,10 @@  Deprecated and removed features, and other changes affecting compatibility:
   ".tmp", to avoid examining temporary files created by the RPM and dpkg
   package managers.
 
+* 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:
 
 * Building on LoongArch requires at a minimum binutils 2.41 for vector
diff --git a/bits/group_member.h b/bits/group_member.h
new file mode 100644
index 0000000000..7c43e7ee06
--- /dev/null
+++ b/bits/group_member.h
@@ -0,0 +1,31 @@ 
+/* group_member declaration
+   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 _BITS_GROUP_MEMBER_H
+# define _BITS_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;
+# endif
+
+#endif /* _BITS_GROUP_MEMBER_H */
diff --git a/posix/Makefile b/posix/Makefile
index c36b9d981e..d3e3c08fd1 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-mmap \
   tst-mmap-offset \
   tst-nanosleep \
@@ -615,6 +617,8 @@  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 0477527a60..b65d4c63d0 100644
--- a/posix/unistd.h
+++ b/posix/unistd.h
@@ -710,10 +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;
-#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/bits/group_member.h b/sysdeps/unix/sysv/linux/bits/group_member.h
new file mode 100644
index 0000000000..0dd9505c76
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/bits/group_member.h
@@ -0,0 +1,32 @@ 
+/* group_member declaration
+   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 _BITS_GROUP_MEMBER_H
+# define _BITS_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");
+# endif
+
+#endif /* _BITS_GROUP_MEMBER_H */