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 <agord...@linux.ibm.com> Reviewed-by: Alexander Potapenko <gli...@google.com> Signed-off-by: Ilya Leoshkevich <i...@linux.ibm.com> --- lib/zlib_dfltcc/dfltcc.h | 1 + lib/zlib_dfltcc/dfltcc_util.h | 28 ++++++++++++++++++++++++++++ 2 files changed, 29 insertions(+) diff --git a/lib/zlib_dfltcc/dfltcc.h b/lib/zlib_dfltcc/dfltcc.h index b96232bdd44d..0f2a16d7a48a 100644 --- a/lib/zlib_dfltcc/dfltcc.h +++ b/lib/zlib_dfltcc/dfltcc.h @@ -80,6 +80,7 @@ struct dfltcc_param_v0 { uint8_t csb[1152]; }; +static_assert(offsetof(struct dfltcc_param_v0, csb) == 384); static_assert(sizeof(struct dfltcc_param_v0) == 1536); #define CVT_CRC32 0 diff --git a/lib/zlib_dfltcc/dfltcc_util.h b/lib/zlib_dfltcc/dfltcc_util.h index 4a46b5009f0d..10509270d822 100644 --- a/lib/zlib_dfltcc/dfltcc_util.h +++ b/lib/zlib_dfltcc/dfltcc_util.h @@ -2,6 +2,8 @@ #ifndef DFLTCC_UTIL_H #define DFLTCC_UTIL_H +#include "dfltcc.h" +#include <linux/kmsan-checks.h> #include <linux/zutil.h> /* @@ -20,6 +22,7 @@ typedef enum { #define DFLTCC_CMPR 2 #define DFLTCC_XPND 4 #define HBT_CIRCULAR (1 << 7) +#define DFLTCC_FN_MASK ((1 << 7) - 1) #define HB_BITS 15 #define HB_SIZE (1 << HB_BITS) @@ -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 +63,30 @@ static inline dfltcc_cc dfltcc( : "cc", "memory"); t2 = r2; t3 = r3; t4 = r4; t5 = r5; + /* + * Unpoison the parameter block and the output buffer. + * This is a no-op in non-KMSAN builds. + */ + switch (fn & DFLTCC_FN_MASK) { + case DFLTCC_QAF: + kmsan_unpoison_memory(param, sizeof(struct dfltcc_qaf_param)); + break; + case DFLTCC_GDHT: + kmsan_unpoison_memory(param, offsetof(struct dfltcc_param_v0, csb)); + break; + case DFLTCC_CMPR: + kmsan_unpoison_memory(param, sizeof(struct dfltcc_param_v0)); + kmsan_unpoison_memory( + orig_t2, + t2 - orig_t2 + + (((struct dfltcc_param_v0 *)param)->sbb == 0 ? 0 : 1)); + break; + case DFLTCC_XPND: + kmsan_unpoison_memory(param, sizeof(struct dfltcc_param_v0)); + kmsan_unpoison_memory(orig_t2, t2 - orig_t2); + break; + } + if (op1) *op1 = t2; if (len1) -- 2.45.1
