Similar to ppoll, the poll.h header needs to redirect the poll call
to a proper fortified ppoll with 64 bit time_t support.
The implementation is straightforward, just need to add a similar
check as __poll_chk and call the 64 bit time_t ppoll version. The
debug fortify tests are also extended to cover 64 bit time_t for
affected ABIs.
Unfortunately it requires an aditional symbol, which makes backport
tricky. One possibility is to add a static inline version if compiler
supports is and call abort instead of __chk_fail, so fortified version
will call __poll64 in the end.
Another possibility is to just remove the fortify support for
_TIME_BITS=64.
Checked on i686-linux-gnu.
I used these shell commands:
../glibc/scripts/update-copyrights $PWD/../gnulib/build-aux/update-copyright
(cd ../glibc && git commit -am"[this commit message]")
and then ignored the output, which consisted lines saying "FOO: warning:
copyright statement not found" for each of 7061 files FOO.
I then removed trailing white space from math/tgmath.h,
support/tst-support-open-dev-null-range.c, and
sysdeps/x86_64/multiarch/strlen-vec.S, to work around the following
obscure pre-commit check failure diagnostics from Savannah. I don't
know why I run into these diagnostics whereas others evidently do not.
remote: *** 912-#endif
remote: *** 913:
remote: *** 914-
remote: *** error: lines with trailing whitespace found
...
remote: *** error: sysdeps/unix/sysv/linux/statx_cp.c: trailing lines
In _FORTIFY_SOURCE=3, the size expression may be non-constant,
resulting in branches in the inline functions remaining intact and
causing a tiny overhead. Clang (and in future, gcc) make sure that
the -1 case is always safe, i.e. any comparison of the generated
expression with (size_t)-1 is always false so that bit is taken care
of. The rest is avoidable since we want the _chk variant whenever we
have a size expression and it's not -1.
Rework the conditionals in a uniform way to clearly indicate two
conditions at compile time:
- Either the size is unknown (-1) or we know at compile time that the
operation length is less than the object size. We can call the
original function in this case. It could be that either the length,
object size or both are non-constant, but the compiler, through
range analysis, is able to fold the *comparison* to a constant.
- The size and length are known and the compiler can see at compile
time that operation length > object size. This is valid grounds for
a warning at compile time, followed by emitting the _chk variant.
For everything else, emit the _chk variant.
This simplifies most of the fortified function implementations and at
the same time, ensures that only one call from _chk or the regular
function is emitted.
Signed-off-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
In the context of a function definition, the size hints imply that the
size of an object pointed to by one parameter is another parameter.
This doesn't make sense for the fortified versions of the functions
since that's the bit it's trying to validate.
This is harmless with __builtin_object_size since it has fairly simple
semantics when it comes to objects passed as function parameters.
With __builtin_dynamic_object_size we could (as my patchset for gcc[1]
already does) use the access attribute to determine the object size in
the general case but it misleads the fortified functions.
Basically the problem occurs when access attributes are present on
regular functions that have inline fortified definitions to generate
_chk variants; the attributes get inherited by these definitions,
causing problems when analyzing them. For example with poll(fds, nfds,
timeout), nfds is hinted using the __attr_access as being the size of
fds.
Now, when analyzing the inline function definition in bits/poll2.h, the
compiler sees that nfds is the size of fds and tries to use that
information in the function body. In _FORTIFY_SOURCE=3 case, where the
object size could be a non-constant expression, this information results
in the conclusion that nfds is the size of fds, which defeats the
purpose of the implementation because we're trying to check here if nfds
does indeed represent the size of fds. Hence for this case, it is best
to not have the access attribute.
With the attributes gone, the expression evaluation should get delayed
until the function is actually inlined into its destinations.
Disable the access attribute for fortified function inline functions
when building at _FORTIFY_SOURCE=3 to make this work better. The
access attributes remain for the _chk variants since they can be used
by the compiler to warn when the caller is passing invalid arguments.
[1] https://gcc.gnu.org/pipermail/gcc-patches/2021-October/581125.html
Signed-off-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
This change continues the improvements to compile-time out of bounds
checking by decorating more APIs with either attribute access, or by
explicitly providing the array bound in APIs such as tmpnam() that
expect arrays of some minimum size as arguments. (The latter feature
is new in GCC 11.)
The only effects of the attribute and/or the array bound is to check
and diagnose calls to the functions that fail to provide a sufficient
number of elements, and the definitions of the functions that access
elements outside the specified bounds. (There is no interplay with
_FORTIFY_SOURCE here yet.)
Tested with GCC 7 through 11 on x86_64-linux.
This patch updates the value of STATX_ATTR_DAX in bits/statx-generic.h
for a change made in Linux 5.10. (As with previous such changes, this
only does anything if glibc is being used with old kernel headers.)
Tested for x86_64.
I used these shell commands:
../glibc/scripts/update-copyrights $PWD/../gnulib/build-aux/update-copyright
(cd ../glibc && git commit -am"[this commit message]")
and then ignored the output, which consisted lines saying "FOO: warning:
copyright statement not found" for each of 6694 files FOO.
I then removed trailing white space from benchtests/bench-pthread-locks.c
and iconvdata/tst-iconv-big5-hkscs-to-2ucs4.c, to work around this
diagnostic from Savannah:
remote: *** pre-commit check failed ...
remote: *** error: lines with trailing whitespace found
remote: error: hook declined to update refs/heads/master
This patch adds the new STATX_MNT_ID, STATX_ATTR_MOUNT_ROOT and
STATX_ATTR_DAX macros from Linux 5.8 to glibc's bits/statx-generic.h.
(As with previous such changes, this only does anything if glibc is
being used with old kernel headers.)
A comment in the Linux kernel headers indicates that STATX_ALL is
deliberately not being changed.
Tested for x86_64.
This patch adds the new STATX_ATTR_VERITY macro from Linux 5.5 to
glibc's bits/statx-generic.h. (This only does anything if glibc is
being used with old kernel headers.)
Tested for x86_64.
Both open and openat load their last argument 'mode' lazily, using
va_arg() only if O_CREAT is found in oflag. This is wrong, mode is also
necessary if O_TMPFILE is in oflag.
By chance on x86_64, the problem wasn't evident when using O_TMPFILE
with open, as the 3rd argument of open, even when not loaded with
va_arg, is left untouched in RDX, where the syscall expects it.
However, openat was not so lucky, and O_TMPFILE couldn't be used: mode
is the 4th argument, in RCX, but the syscall expects its 4th argument in
a different register than the glibc wrapper, in R10.
Introduce a macro __OPEN_NEEDS_MODE (oflag) to test if either O_CREAT or
O_TMPFILE is set in oflag.
Tested on Linux x86_64.
[BZ #17523]
* io/fcntl.h (__OPEN_NEEDS_MODE): New macro.
* io/bits/fcntl2.h (open): Use it.
(openat): Likewise.
* io/open.c (__libc_open): Likewise.
* io/open64.c (__libc_open64): Likewise.
* io/open64_2.c (__open64_2): Likewise.
* io/open_2.c (__open_2): Likewise.
* io/openat.c (__openat): Likewise.
* io/openat64.c (__openat64): Likewise.
* io/openat64_2.c (__openat64_2): Likewise.
* io/openat_2.c (__openat_2): Likewise.
* sysdeps/mach/hurd/open.c (__libc_open): Likewise.
* sysdeps/mach/hurd/openat.c (__openat): Likewise.
* sysdeps/posix/open64.c (__libc_open64): Likewise.
* sysdeps/unix/sysv/linux/dl-openat64.c (openat64): Likewise.
* sysdeps/unix/sysv/linux/generic/open.c (__libc_open): Likewise.
(__open_nocancel): Likewise.
* sysdeps/unix/sysv/linux/generic/open64.c (__libc_open64): Likewise.
* sysdeps/unix/sysv/linux/open64.c (__libc_open64): Likewise.
* sysdeps/unix/sysv/linux/openat.c (__OPENAT): Likewise.
* rt/Makefile (headers): Add bits/mqueue2.h.
* rt/mqueue.h: Include bits/mqueue2.h if -D_FORTIFY_SOURCE=2,
optimizing with GCC and __va_arg_pack_len is defined.
* rt/bits/mqueue2.h: New file.
* rt/mq_open.c (__mq_open): Renamed from mq_open.
(mq_open): New strong_alias.
(__mq_open_2): New function.
* sysdeps/unix/sysv/linux/mq_open.c (__mq_open): Renamed from mq_open.
(mq_open): New strong_alias.
(__mq_open_2): New function.
* debug/Versions (libc): Export __fortify_fail@@GLIBC_PRIVATE.
* Versions.def (librt): Add GLIBC_2.7 version.
* debug/fortify_fail.c (__fortify_fail): Add libc_hidden_def.
* include/stdio.h (__fortify_fail): Add libc_hidden_proto.
* misc/sys/cdefs.h (__errordecl, __va_arg_pack_len): Define.
* io/fcntl.h: Include bits/fcntl2.h when __va_arg_pack_len
is defined rather than when not C++.
* io/bits/fcntl2.h (__open_alias, __open64_alias, __openat_alias,
__openat64_alias): New redirects.
(__open_too_many_args, __open_missing_mode, __open64_too_many_args,
__open64_missing_mode, __openat_too_many_args, __openat_missing_mode,
__openat64_too_many_args, __openat64_missing_mode): New __errordecls.
(open, open64, openat, openat64): Rewrite as __extern_always_inline
functions instead of function-like macros.
__extension__ around the whole statement expression.
2007-08-04 Jakub Jelinek <jakub@redhat.com>
* io/bits/fcntl2.h (open, open64, openat, openat64): Add
__extension__ around the whole statement expression.
(open): Fix comment typos. Don't call __open_2 if flags
is a compile time constant without O_CREAT.
(__open64_2): Add nonnull attribute.
(open64): Fix comment typos. Don't call __open64_2 if flags
is a compile time constant without O_CREAT.
(__openat_2): Add nonnull attribute, fix nonnull attribute
on redirect.
(openat): Fix comment typos. Don't call __openat_2 if flags
is a compile time constant without O_CREAT.
(__openat64_2): Add nonnull attribute, fix nonnull attribute
on redirect.
(openat64): Fix comment typos. Don't call __openat64_2 if flags
is a compile time constant without O_CREAT.
