An overread condition in memccpy(dst, src, c, len) would occur if
src does not cross a 16 byte boundary and there is no instance of
c between *src and the next 16 byte boundary. This could cause a
read fault if src is just before the end of a page and the next page
is unmapped or unreadable.
The bug is a consequence of basing memccpy() on the strlcpy() code:
whereas strlcpy() assumes that src is a nul-terminated string and
hence a terminator is always present, c may not be present at all in
the source string. It was not caught earlier due to insufficient
unit test design.
As a part of the fix, the function is refactored such that the runt
case (buffer length from last alignment boundary between 1 and 32 B)
is handled separately. This reduces the number of conditional
branches on all code paths and simplifies the handling of early
matches in the non-runt case. Performance is improved slightly.
os: FreeBSD
arch: amd64
cpu: 11th Gen Intel(R) Core(TM) i7-1165G7 @ 2.80GHz
│ memccpy.unfixed.out │ memccpy.fixed.out │
│ sec/op │ sec/op vs base │
Short 66.76µ ± 0% 62.45µ ± 1% -6.44% (p=0.000 n=20)
Mid 7.938µ ± 0% 7.967µ ± 0% +0.36% (p=0.001 n=20)
Long 3.577µ ± 0% 3.577µ ± 0% ~ (p=0.429 n=20)
geomean 12.38µ 12.12µ -2.08%
│ memccpy.unfixed.out │ memccpy.fixed.out │
│ B/s │ B/s vs base │
Short 1.744Gi ± 0% 1.864Gi ± 1% +6.89% (p=0.000 n=20)
Mid 14.67Gi ± 0% 14.61Gi ± 0% -0.36% (p=0.001 n=20)
Long 32.55Gi ± 0% 32.55Gi ± 0% ~ (p=0.429 n=20)
geomean 9.407Gi 9.606Gi +2.12%
Reported by: getz
Reviewed by: getz
Approved by: mjg (blanket, via IRC)
See also: D46051
MFC: stable/14
Event: GSoC 2024
Differential Revision: https://reviews.freebsd.org/D46052
See 8164d511d6a6 ("libc/tests: Fix installation without MK_TOOLCHAIN")
for some background. Here we should really be testing MK_CLANG instead,
since that's what gates compilation of libclang_rt.
Fixes: 8164d511d6a6 ("libc/tests: Fix installation without MK_TOOLCHAIN")
(cherry picked from commit da925fcebf397cc3bfc74b7aa9757efd6231aa00)
There is some exotic conditional logic here to avoid building a
particular test if a certain UBSAN library isn't present in the
toolchain sysroot. This causes build failures for me when doing an
"installworld WITHOUT_TOOLCHAIN=", which I do frequently during tests.
I believe the problem is that SYSROOT is unset during installworld, so
the build sees the host's copy of libclang_rt.ubsan_standalone.a and
then tries to install a binary that wasn't built during buildworld. Try
to make the check a bit less fragile.
Reviewed by: dim
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D45035
(cherry picked from commit 8164d511d6a6053df82911e7d4ebb34fff3d765c)
Before this commit, we only had the capability to check if a specific
capability was set (using cap_rights_is_set function). However, there
was no efficient method to determine if a cap_rights_t structure doesn't
contain any capability. The cap_rights_is_empty function addresses
this gap.
PR: 275330
Reported by: vini.ipsmaker@gmail.com
Reviewed by: emaste, markj
Differential Revision: https://reviews.freebsd.org/D42780
(cherry picked from commit a7100ae23aca07976926bd8d50223c45149f65d6)
To fix WITHOUT_NIS build. Building yp_xdr.c is gated by MK_NIS.
PR: 279270
Reported by: peterj
Reported by: matteo
Reported by: Michael Dexter's Build Option Survey run
Reviewed by: brooks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D45347
(cherry picked from commit 61639bb3fc5abe0bb7b096e643b51c30703ac432)
access(), eaccess() and faccessat() will always dereference
symbolic links.
So add a note in the manual page, that lstat(2) should be
used in the case of symbolic links.
PR: 262895
Reviewed by: gbe, pauamma_gundo.com
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D44890
(cherry picked from commit 421025a274fb5759b3ecc8bdb30b24db830b45ae)
Capsicum-sandboxed applications generally cannot use dlopen, as absolute
and cwd-relative paths cannot be accessed. Mention that fdlopen is
useful for sandboxed applications.
PR: 277169
Reviewed by: markj, oshogbo
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D45108
(cherry picked from commit d84fd89ecd404ffbf629381d2dde14fd79b39402)
The CLOCK_* constants are "defined variable or preprocessor constants"
and so use .Dv.
Reviewed by: imp
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D45106
(cherry picked from commit 2d29d2ecebf8ea19221995b3ea2e3a7ac700bf81)
As kib@ noted:
> Obviously gettimeofday(2) is not going to be removed
> even in the far future.
Reported by: kib
Fixes: 4395d3ced5cf Document that gettimeofday() is obsolescent
MFC after: 3 days
(cherry picked from commit 6662c2312e956439652ce2d06b42753b6a78fc61)
Change .Xr reference to .Fn, which quiets a mandoc warning.
Reviewed by: mhorne
MFC after: 3 days
Pull Request: https://github.com/freebsd/freebsd-src/pull/1135
(cherry picked from commit d3de1bd429bc51fbbcb37fadaf2581461edf848b)
* Mention that mktime() and timegm() set errno on failure.
* Correctly determining whether mktime() / timegm() succeeded with
arbitrary input (where -1 can be a valid result) is non-trivial.
Document the recommended procedure.
PR: 277863
MFC after: 1 week
Reviewed by: pauamma_gundo.com, gbe
Differential Revision: https://reviews.freebsd.org/D44503
(cherry picked from commit 7534109d13a6cdb22e78d9d4c0a0cd5efd323c45)
In the errno list, add an explicit note and reference to the note in the
STANDARDS section.
When O_NOFOLLOW is specified and the target is a symbolic link FreeBSD
sets errno to a value different than that specified by POSIX. Commit
295159dfa3 added a note to this effect, but I missed it when reading
through the list of errno values.
PR: 214633
Reviewed by: markj
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D43618
(cherry picked from commit ea6a6b63e1fd304e790c8ed7627caf5e3ba52bc7)
Add the Branch Target Identification (BTI) note to libc assembly
sources. As all obect files need the note for the library to have it
we need to insert it in all asm files.
Reviewed by: emaste, markj
Sponsored by: Arm Ltd
Differential Revision: https://reviews.freebsd.org/D42228
(cherry picked from commit fd5aaf2ea0178b03aa93c35245053247e5d3840c)
