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authorIgor Ostapenko <pm@igoro.pro>2023-12-12 18:26:21 +0000
committerKristof Provost <kp@FreeBSD.org>2023-12-12 20:49:14 +0000
commit0c511bafdd5b309505c13c8dc7c6816686d1e103 (patch)
tree39a01ddaa5ecd29ab40c6ddae31a4822000b8a40
parent6fa843f6e647a1a1e0e42af1e7abc9e903699f31 (diff)
downloadsrc-0c511bafdd5b309505c13c8dc7c6816686d1e103.tar.gz
src-0c511bafdd5b309505c13c8dc7c6816686d1e103.zip
netlink: fix snl_writer and linear_buffer re-allocation logic
- Use the correct base pointer after re-allocation to avoid buffer overflows. - Maintain correct snl_writer.size, which avoids redundant memory allocation, e.g. a need for ~1k bytes may end up with ~32k linear_buffer actually allocated. This fixes a pfctl regression at least for armv7 after the addrule logic migration to netlink: ffbf25951e7b ("pf: convert rule addition to netlink") The add rule command creates a bigger than default size netlink requests which triggers the re-allocation logic. Reviewed by: kp MFC after: 2 weeks Differnetial Revision: https://reviews.freebsd.org/D43003
-rw-r--r--sys/netlink/netlink_snl.h18
1 files changed, 11 insertions, 7 deletions
diff --git a/sys/netlink/netlink_snl.h b/sys/netlink/netlink_snl.h
index 8bb7b076b7b7..7bdf5424ddf3 100644
--- a/sys/netlink/netlink_snl.h
+++ b/sys/netlink/netlink_snl.h
@@ -1036,19 +1036,23 @@ snl_realloc_msg_buffer(struct snl_writer *nw, size_t sz)
if (nw->error)
return (false);
- void *new_base = snl_allocz(nw->ss, new_size);
- if (new_base == NULL) {
+ if (snl_allocz(nw->ss, new_size) == NULL) {
nw->error = true;
return (false);
}
+ nw->size = new_size;
- memcpy(new_base, nw->base, nw->offset);
- if (nw->hdr != NULL) {
- int hdr_off = (char *)(nw->hdr) - nw->base;
+ void *new_base = nw->ss->lb->base;
+ if (new_base != nw->base) {
+ memcpy(new_base, nw->base, nw->offset);
+ if (nw->hdr != NULL) {
+ int hdr_off = (char *)(nw->hdr) - nw->base;
- nw->hdr = (struct nlmsghdr *)(void *)((char *)new_base + hdr_off);
+ nw->hdr = (struct nlmsghdr *)
+ (void *)((char *)new_base + hdr_off);
+ }
+ nw->base = new_base;
}
- nw->base = new_base;
return (true);
}