* [PATCH v5] posix: Deprecate group_member for Linux
@ 2023-10-20 17:42 Joe Simmons-Talbott
2023-10-30 11:58 ` Joe Simmons-Talbott
0 siblings, 1 reply; 2+ messages in thread
From: Joe Simmons-Talbott @ 2023-10-20 17:42 UTC (permalink / raw)
To: libc-alpha; +Cc: Joe Simmons-Talbott
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
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH v5] posix: Deprecate group_member for Linux
2023-10-20 17:42 [PATCH v5] posix: Deprecate group_member for Linux Joe Simmons-Talbott
@ 2023-10-30 11:58 ` Joe Simmons-Talbott
0 siblings, 0 replies; 2+ messages in thread
From: Joe Simmons-Talbott @ 2023-10-30 11:58 UTC (permalink / raw)
To: libc-alpha
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
>
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