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| author | Rich Felker <dalias@aerifal.cx> | 2016-05-22 18:49:59 -0400 |
|---|---|---|
| committer | Rich Felker <dalias@aerifal.cx> | 2016-05-22 18:49:59 -0400 |
| commit | 81fb75a1d75c20d97292cbbe4cde6a1e65871abe (patch) | |
| tree | 71138623e144edd910490f327696b546e14f7d67 | |
| parent | 51eeb6ebc94d965768143c45e9f39b0a7998bdbd (diff) | |
| download | musl-81fb75a1d75c20d97292cbbe4cde6a1e65871abe.tar.gz musl-81fb75a1d75c20d97292cbbe4cde6a1e65871abe.tar.bz2 musl-81fb75a1d75c20d97292cbbe4cde6a1e65871abe.tar.xz musl-81fb75a1d75c20d97292cbbe4cde6a1e65871abe.zip | |
fix undefined pointer arithmetic in CMSG_NXTHDR macro
previously, the only way the stopping condition could be met with
correct lengths in the headers invoked undefined behavior, adding
sizeof(struct cmsghdr) beyond the end of the cmsg buffer.
instead, compute and compare sizes rather than pointers.
| -rw-r--r-- | include/sys/socket.h | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/include/sys/socket.h b/include/sys/socket.h index fd653490..67883750 100644 --- a/include/sys/socket.h +++ b/include/sys/socket.h @@ -266,9 +266,9 @@ struct linger #define __MHDR_END(mhdr) ((unsigned char *)(mhdr)->msg_control + (mhdr)->msg_controllen) #define CMSG_DATA(cmsg) ((unsigned char *) (((struct cmsghdr *)(cmsg)) + 1)) -#define CMSG_NXTHDR(mhdr, cmsg) ((cmsg)->cmsg_len < sizeof (struct cmsghdr) ? (struct cmsghdr *)0 : \ - (__CMSG_NEXT(cmsg) + sizeof (struct cmsghdr) >= __MHDR_END(mhdr) ? (struct cmsghdr *)0 : \ - ((struct cmsghdr *)__CMSG_NEXT(cmsg)))) +#define CMSG_NXTHDR(mhdr, cmsg) ((cmsg)->cmsg_len < sizeof (struct cmsghdr) || \ + __CMSG_LEN(cmsg) + sizeof(struct cmsghdr) >= __MHDR_END(mhdr) - (unsigned char *)(cmsg) \ + ? 0 : (struct cmsghdr *)__CMSG_NEXT(cmsg)) #define CMSG_FIRSTHDR(mhdr) ((size_t) (mhdr)->msg_controllen >= sizeof (struct cmsghdr) ? (struct cmsghdr *) (mhdr)->msg_control : (struct cmsghdr *) 0) #define CMSG_ALIGN(len) (((len) + sizeof (size_t) - 1) & (size_t) ~(sizeof (size_t) - 1)) |