kernel/linux.git/lib/buildid.c, branch v6.6.132

lib/buildid: Handle memfd_secret() files in build_id_parse()

2025-03-22T19:50:48+00:00

commit 5ac9b4e935dfc6af41eee2ddc21deb5c36507a9f upstream. >From memfd_secret(2) manpage: The memory areas backing the file created with memfd_secret(2) are visible only to the processes that have access to the file descriptor. The memory region is removed from the kernel page tables and only the page tables of the processes holding the file descriptor map the corresponding physical memory. (Thus, the pages in the region can't be accessed by the kernel itself, so that, for example, pointers to the region can't be passed to system calls.) We need to handle this special case gracefully in build ID fetching code. Return -EFAULT whenever secretmem file is passed to build_id_parse() family of APIs. Original report and repro can be found in [0]. [0] https://lore.kernel.org/bpf/ZwyG8Uro%2FSyTXAni@ly-workstation/ Fixes: de3ec364c3c3 ("lib/buildid: add single folio-based file reader abstraction") Reported-by: Yi Lai Suggested-by: Shakeel Butt Signed-off-by: Andrii Nakryiko Signed-off-by: Daniel Borkmann Acked-by: Shakeel Butt Link: https://lore.kernel.org/bpf/20241017175431.6183-A-hca@linux.ibm.com Link: https://lore.kernel.org/bpf/20241017174713.2157873-1-andrii@kernel.org [ Chen Linxuan: backport same logic without folio-based changes ] Fixes: 88a16a130933 ("perf: Add build id data in mmap2 event") Signed-off-by: Chen Linxuan Signed-off-by: Greg Kroah-Hartman

lib/buildid: Fix build ID parsing logic

2024-11-22T14:38:36+00:00

The parse_build_id_buf does not account Elf32_Nhdr header size when getting the build id data pointer and returns wrong build id data as result. This is problem only for stable trees that merged c83a80d8b84f fix, the upstream build id code was refactored and returns proper build id. Acked-by: Andrii Nakryiko Fixes: c83a80d8b84f ("lib/buildid: harden build ID parsing logic") Signed-off-by: Jiri Olsa Signed-off-by: Greg Kroah-Hartman

lib/buildid: harden build ID parsing logic

2024-10-10T09:58:03+00:00

[ Upstream commit 905415ff3ffb1d7e5afa62bacabd79776bd24606 ] Harden build ID parsing logic, adding explicit READ_ONCE() where it's important to have a consistent value read and validated just once. Also, as pointed out by Andi Kleen, we need to make sure that entire ELF note is within a page bounds, so move the overflow check up and add an extra note_size boundaries validation. Fixes tag below points to the code that moved this code into lib/buildid.c, and then subsequently was used in perf subsystem, making this code exposed to perf_event_open() users in v5.12+. Cc: stable@vger.kernel.org Reviewed-by: Eduard Zingerman Reviewed-by: Jann Horn Suggested-by: Andi Kleen Fixes: bd7525dacd7e ("bpf: Move stack_map_get_build_id into lib") Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/r/20240829174232.3133883-2-andrii@kernel.org Signed-off-by: Alexei Starovoitov Signed-off-by: Sasha Levin

build-id: require program headers to be right after ELF header

2024-10-10T09:58:03+00:00

[ Upstream commit 961a2851324561caed579764ffbee3db82b32829 ] Neither ELF spec not ELF loader require program header to be placed right after ELF header, but build-id code very much assumes such placement: See find_get_page(vma->vm_file->f_mapping, 0); line and checks against PAGE_SIZE. Returns errors for now until someone rewrites build-id parser to be more inline with load_elf_binary(). Link: https://lkml.kernel.org/r/d58bc281-6ca7-467a-9a64-40fa214bd63e@p183 Signed-off-by: Alexey Dobriyan Reviewed-by: Jiri Olsa Signed-off-by: Andrew Morton Stable-dep-of: 905415ff3ffb ("lib/buildid: harden build ID parsing logic") Signed-off-by: Sasha Levin

ELF: fix all "Elf" typos

2023-04-08T20:45:37+00:00

ELF is acronym and therefore should be spelled in all caps. I left one exception at Documentation/arm/nwfpe/nwfpe.rst which looks like being written in the first person. Link: https://lkml.kernel.org/r/Y/3wGWQviIOkyLJW@p183 Signed-off-by: Alexey Dobriyan Signed-off-by: Andrew Morton

kdump: use vmlinux_build_id to simplify

2021-07-08T18:48:22+00:00

We can use the vmlinux_build_id array here now instead of open coding it. This mostly consolidates code. Link: https://lkml.kernel.org/r/20210511003845.2429846-14-swboyd@chromium.org Signed-off-by: Stephen Boyd Cc: Jiri Olsa Cc: Alexei Starovoitov Cc: Jessica Yu Cc: Evan Green Cc: Hsin-Yi Wang Cc: Dave Young Cc: Baoquan He Cc: Vivek Goyal Cc: Andy Shevchenko Cc: Borislav Petkov Cc: Catalin Marinas Cc: Ingo Molnar Cc: Konstantin Khlebnikov Cc: Matthew Wilcox Cc: Petr Mladek Cc: Rasmus Villemoes Cc: Sasha Levin Cc: Sergey Senozhatsky Cc: Steven Rostedt Cc: Thomas Gleixner Cc: Will Deacon Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

buildid: fix kernel-doc notation

2021-07-08T18:48:22+00:00

Kernel doc should use "Return:" instead of "Returns" to properly reflect the return values. Link: https://lkml.kernel.org/r/20210511003845.2429846-13-swboyd@chromium.org Signed-off-by: Stephen Boyd Cc: Jiri Olsa Cc: Alexei Starovoitov Cc: Jessica Yu Cc: Evan Green Cc: Hsin-Yi Wang Cc: Andy Shevchenko Cc: Baoquan He Cc: Borislav Petkov Cc: Catalin Marinas Cc: Dave Young Cc: Ingo Molnar Cc: Konstantin Khlebnikov Cc: Matthew Wilcox Cc: Petr Mladek Cc: Rasmus Villemoes Cc: Sasha Levin Cc: Sergey Senozhatsky Cc: Steven Rostedt Cc: Thomas Gleixner Cc: Vivek Goyal Cc: Will Deacon Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

buildid: mark some arguments const

2021-07-08T18:48:22+00:00

These arguments are never modified so they can be marked const to indicate as such. Link: https://lkml.kernel.org/r/20210511003845.2429846-12-swboyd@chromium.org Signed-off-by: Stephen Boyd Cc: Jiri Olsa Cc: Alexei Starovoitov Cc: Jessica Yu Cc: Evan Green Cc: Hsin-Yi Wang Cc: Andy Shevchenko Cc: Baoquan He Cc: Borislav Petkov Cc: Catalin Marinas Cc: Dave Young Cc: Ingo Molnar Cc: Konstantin Khlebnikov Cc: Matthew Wilcox Cc: Petr Mladek Cc: Rasmus Villemoes Cc: Sasha Levin Cc: Sergey Senozhatsky Cc: Steven Rostedt Cc: Thomas Gleixner Cc: Vivek Goyal Cc: Will Deacon Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

dump_stack: add vmlinux build ID to stack traces

2021-07-08T18:48:22+00:00

Add the running kernel's build ID[1] to the stacktrace information header. This makes it simpler for developers to locate the vmlinux with full debuginfo for a particular kernel stacktrace. Combined with scripts/decode_stracktrace.sh, a developer can download the correct vmlinux from a debuginfod[2] server and find the exact file and line number for the functions plus offsets in a stacktrace. This is especially useful for pstore crash debugging where the kernel crashes are recorded in the pstore logs and the recovery kernel is different or the debuginfo doesn't exist on the device due to space concerns (the data can be large and a security concern). The stacktrace can be analyzed after the crash by using the build ID to find the matching vmlinux and understand where in the function something went wrong. Example stacktrace from lkdtm: WARNING: CPU: 4 PID: 3255 at drivers/misc/lkdtm/bugs.c:83 lkdtm_WARNING+0x28/0x30 [lkdtm] Modules linked in: lkdtm rfcomm algif_hash algif_skcipher af_alg xt_cgroup uinput xt_MASQUERADE CPU: 4 PID: 3255 Comm: bash Not tainted 5.11 #3 aa23f7a1231c229de205662d5a9e0d4c580f19a1 Hardware name: Google Lazor (rev3+) with KB Backlight (DT) pstate: 00400009 (nzcv daif +PAN -UAO -TCO BTYPE=--) pc : lkdtm_WARNING+0x28/0x30 [lkdtm] The hex string aa23f7a1231c229de205662d5a9e0d4c580f19a1 is the build ID, following the kernel version number. Put it all behind a config option, STACKTRACE_BUILD_ID, so that kernel developers can remove this information if they decide it is too much. Link: https://lkml.kernel.org/r/20210511003845.2429846-5-swboyd@chromium.org Link: https://fedoraproject.org/wiki/Releases/FeatureBuildId [1] Link: https://sourceware.org/elfutils/Debuginfod.html [2] Signed-off-by: Stephen Boyd Cc: Jiri Olsa Cc: Alexei Starovoitov Cc: Jessica Yu Cc: Evan Green Cc: Hsin-Yi Wang Cc: Petr Mladek Cc: Steven Rostedt Cc: Andy Shevchenko Cc: Matthew Wilcox Cc: Baoquan He Cc: Borislav Petkov Cc: Catalin Marinas Cc: Dave Young Cc: Ingo Molnar Cc: Konstantin Khlebnikov Cc: Rasmus Villemoes Cc: Sasha Levin Cc: Sergey Senozhatsky Cc: Thomas Gleixner Cc: Vivek Goyal Cc: Will Deacon Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

buildid: stash away kernels build ID on init

2021-07-08T18:48:22+00:00

Parse the kernel's build ID at initialization so that other code can print a hex format string representation of the running kernel's build ID. This will be used in the kdump and dump_stack code so that developers can easily locate the vmlinux debug symbols for a crash/stacktrace. [swboyd@chromium.org: fix implicit declaration of init_vmlinux_build_id()] Link: https://lkml.kernel.org/r/CAE-0n51UjTbay8N9FXAyE7_aR2+ePrQnKSRJ0gbmRsXtcLBVaw@mail.gmail.com Link: https://lkml.kernel.org/r/20210511003845.2429846-4-swboyd@chromium.org Signed-off-by: Stephen Boyd Acked-by: Baoquan He Cc: Jiri Olsa Cc: Alexei Starovoitov Cc: Jessica Yu Cc: Evan Green Cc: Hsin-Yi Wang Cc: Dave Young Cc: Vivek Goyal Cc: Andy Shevchenko Cc: Borislav Petkov Cc: Catalin Marinas Cc: Ingo Molnar Cc: Konstantin Khlebnikov Cc: Matthew Wilcox Cc: Petr Mladek Cc: Rasmus Villemoes Cc: Sasha Levin Cc: Sergey Senozhatsky Cc: Steven Rostedt Cc: Thomas Gleixner Cc: Will Deacon Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds