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| author | Palmer Dabbelt <palmer@rivosinc.com> | 2022-06-23 14:49:32 -0700 |
|---|---|---|
| committer | Andreas K. Hüttel <dilfridge@gentoo.org> | 2024-06-26 12:45:43 +0200 |
| commit | 07fe71f59b13bbc336ece3ec9ef94dd95c9e0511 (patch) | |
| tree | db2786b8cafcf6a57e66225af50ddaaa2a8583d2 | |
| parent | a10b6ad471d7b528149f5ff32eef2f1c1dc1213c (diff) | |
| download | glibc-07fe71f59b13bbc336ece3ec9ef94dd95c9e0511.tar.gz glibc-07fe71f59b13bbc336ece3ec9ef94dd95c9e0511.tar.xz glibc-07fe71f59b13bbc336ece3ec9ef94dd95c9e0511.zip | |
arm: Avoid UB in elf_machine_rel()
This recently came up during a cleanup to remove misaligned accesses from the RISC-V port. Link: https://sourceware.org/pipermail/libc-alpha/2022-June/139961.html Suggested-by: Adhemerval Zanella <adhemerval.zanella@linaro.org> Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com> Reviewed-by: Fangrui Song <maskray@google.com>
| -rw-r--r-- | sysdeps/arm/dl-machine.h | 9 |
1 files changed, 4 insertions, 5 deletions
diff --git a/sysdeps/arm/dl-machine.h b/sysdeps/arm/dl-machine.h index dd1a0f6b6e..9186831be3 100644 --- a/sysdeps/arm/dl-machine.h +++ b/sysdeps/arm/dl-machine.h @@ -349,10 +349,7 @@ elf_machine_rel (struct link_map *map, struct r_scope_elem *scope[], break; case R_ARM_ABS32: { - struct unaligned - { - Elf32_Addr x; - } __attribute__ ((packed, may_alias)); + ElfW(Addr) tmp; # ifndef RTLD_BOOTSTRAP /* This is defined in rtld.c, but nowhere in the static libc.a; make the reference weak so static programs can @@ -372,7 +369,9 @@ elf_machine_rel (struct link_map *map, struct r_scope_elem *scope[], value -= SYMBOL_ADDRESS (map, refsym, true); # endif /* Support relocations on mis-aligned offsets. */ - ((struct unaligned *) reloc_addr)->x += value; + memcpy (&tmp, reloc_addr, sizeof tmp); + tmp += value; + memcpy (reloc_addr, &tmp, sizeof tmp); break; } case R_ARM_TLS_DESC: |