On Thu, Dec 14, 2023 at 12:36 AM Ilya Leoshkevich <iii@xxxxxxxxxxxxx> wrote: > > The constraints of the DFLTCC inline assembly are not precise: they > do not communicate the size of the output buffers to the compiler, so > it cannot automatically instrument it. > > Add the manual kmsan_unpoison_memory() calls for the output buffers. > The logic is the same as in [1]. > > [1] https://github.com/zlib-ng/zlib-ng/commit/1f5ddcc009ac3511e99fc88736a9e1a6381168c5 > > Reported-by: Alexander Gordeev <agordeev@xxxxxxxxxxxxx> > Signed-off-by: Ilya Leoshkevich <iii@xxxxxxxxxxxxx> Reviewed-by: Alexander Potapenko <glider@xxxxxxxxxx> > @@ -34,6 +37,7 @@ static inline dfltcc_cc dfltcc( > ) > { > Byte *t2 = op1 ? *op1 : NULL; > + unsigned char *orig_t2 = t2; > size_t t3 = len1 ? *len1 : 0; > const Byte *t4 = op2 ? *op2 : NULL; > size_t t5 = len2 ? *len2 : 0; > @@ -59,6 +63,26 @@ static inline dfltcc_cc dfltcc( > : "cc", "memory"); > t2 = r2; t3 = r3; t4 = r4; t5 = r5; > > + switch (fn & DFLTCC_FN_MASK) { It might be a good idea to add a comment explaining what this block of code does. (And that it is no-op in non-KMSAN builds)
