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| author | Kees Cook <keescook@chromium.org> | 2021-11-18 12:36:04 -0800 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2021-12-02 10:39:00 +1100 |
| commit | 62ea67e31981bca95ec16c37e2a1fba68f3dd8c5 (patch) | |
| tree | 48bd43cd095317cd076eaa4f542289cfbb6f60d6 /arch/powerpc/kernel | |
| parent | af11dee4361b3519981fa04d014873f9d9edd6ac (diff) | |
| download | linux-62ea67e31981bca95ec16c37e2a1fba68f3dd8c5.tar.bz2 | |
powerpc/signal32: Use struct_group() to zero spe regs
In preparation for FORTIFY_SOURCE performing compile-time and run-time
field bounds checking for memset(), avoid intentionally writing across
neighboring fields.
Add a struct_group() for the spe registers so that memset() can correctly reason
about the size:
In function 'fortify_memset_chk',
inlined from 'restore_user_regs.part.0' at arch/powerpc/kernel/signal_32.c:539:3:
>> include/linux/fortify-string.h:195:4: error: call to '__write_overflow_field' declared with attribute warning: detected write beyond size of field (1st parameter); maybe use struct_group()? [-Werror=attribute-warning]
195 | __write_overflow_field();
| ^~~~~~~~~~~~~~~~~~~~~~~~
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211118203604.1288379-1-keescook@chromium.org
Diffstat (limited to 'arch/powerpc/kernel')
| -rw-r--r-- | arch/powerpc/kernel/signal_32.c | 14 |
1 files changed, 9 insertions, 5 deletions
diff --git a/arch/powerpc/kernel/signal_32.c b/arch/powerpc/kernel/signal_32.c index 3e053e2fd6b6..d84c434b2b78 100644 --- a/arch/powerpc/kernel/signal_32.c +++ b/arch/powerpc/kernel/signal_32.c @@ -527,16 +527,20 @@ static long restore_user_regs(struct pt_regs *regs, regs_set_return_msr(regs, regs->msr & ~(MSR_FP | MSR_FE0 | MSR_FE1)); #ifdef CONFIG_SPE - /* force the process to reload the spe registers from - current->thread when it next does spe instructions */ + /* + * Force the process to reload the spe registers from + * current->thread when it next does spe instructions. + * Since this is user ABI, we must enforce the sizing. + */ + BUILD_BUG_ON(sizeof(current->thread.spe) != ELF_NEVRREG * sizeof(u32)); regs_set_return_msr(regs, regs->msr & ~MSR_SPE); if (msr & MSR_SPE) { /* restore spe registers from the stack */ - unsafe_copy_from_user(current->thread.evr, &sr->mc_vregs, - ELF_NEVRREG * sizeof(u32), failed); + unsafe_copy_from_user(¤t->thread.spe, &sr->mc_vregs, + sizeof(current->thread.spe), failed); current->thread.used_spe = true; } else if (current->thread.used_spe) - memset(current->thread.evr, 0, ELF_NEVRREG * sizeof(u32)); + memset(¤t->thread.spe, 0, sizeof(current->thread.spe)); /* Always get SPEFSCR back */ unsafe_get_user(current->thread.spefscr, (u32 __user *)&sr->mc_vregs + ELF_NEVRREG, failed); |