On Sat, Feb 15, 2025 at 12:56:08PM +0100, Stefano Brivio wrote:

Checked against musl 1.2.5.

Signed-off-by: Stefano Brivio

Reviewed-by: David Gibson

--- v3: Now 100% more trusted, with cppcheck absolutely positive about us initialising 'buf'.

v2: Now 100% more tested: don't try to use the whole buffer as msg_controllen.

passt-repair.c | 4 +++- repair.c | 13 +++++++++---- 2 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/passt-repair.c b/passt-repair.c index 1174ae3..e0c366e 100644 --- a/passt-repair.c +++ b/passt-repair.c @@ -63,6 +63,7 @@ int main(int argc, char **argv) struct cmsghdr *cmsg; struct msghdr msg; struct iovec iov; + size_t cmsg_len; int op;

prctl(PR_SET_DUMPABLE, 0); @@ -138,8 +139,9 @@ loop: } } if (!n) { + cmsg_len = cmsg->cmsg_len; /* socklen_t is 'unsigned' on musl */ fprintf(stderr, "Invalid ancillary data length %zu from peer\n", - cmsg->cmsg_len); + cmsg_len); _exit(1); }

diff --git a/repair.c b/repair.c index d288617..dac28a6 100644 --- a/repair.c +++ b/repair.c @@ -13,6 +13,7 @@ */

#include +#include #include

#include "util.h" @@ -145,9 +146,9 @@ void repair_handler(struct ctx *c, uint32_t events) */ int repair_flush(struct ctx *c) { - struct iovec iov = { &repair_cmd, sizeof(repair_cmd) }; char buf[CMSG_SPACE(sizeof(int) * SCM_MAX_FD)] - __attribute__ ((aligned(__alignof__(struct cmsghdr)))); + __attribute__ ((aligned(__alignof__(struct cmsghdr)))) = { 0 }; + struct iovec iov = { &repair_cmd, sizeof(repair_cmd) }; struct cmsghdr *cmsg; struct msghdr msg; int8_t reply; @@ -155,8 +156,12 @@ int repair_flush(struct ctx *c) if (!repair_nfds) return 0;

- msg = (struct msghdr){ NULL, 0, &iov, 1, - buf, CMSG_SPACE(sizeof(int) * repair_nfds), 0 }; + msg = (struct msghdr){ .msg_name = NULL, .msg_namelen = 0, + .msg_iov = &iov, .msg_iovlen = 1, + .msg_control = buf, + .msg_controllen = CMSG_SPACE(sizeof(int) * + repair_nfds), + .msg_flags = 0 }; cmsg = CMSG_FIRSTHDR(&msg);

cmsg->cmsg_level = SOL_SOCKET;

-- David Gibson (he or they) | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you, not the other way | around. http://www.ozlabs.org/~dgibson