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| author | Alexey Izbyshev <izbyshev@ispras.ru> | 2023-01-29 19:46:51 +0300 |
|---|---|---|
| committer | Rich Felker <dalias@aerifal.cx> | 2023-02-27 10:03:06 -0500 |
| commit | 9b132e556774c744f9052581d2d8d0fab417e97c (patch) | |
| tree | cbb516502c92f69bb6b01c82dbb7c30fed845c56 /src/network/lookup_name.c | |
| parent | 12590c8bbd04ea484cee86812e2258fbdfca0e59 (diff) | |
| download | musl-9b132e556774c744f9052581d2d8d0fab417e97c.tar.gz musl-9b132e556774c744f9052581d2d8d0fab417e97c.tar.xz musl-9b132e556774c744f9052581d2d8d0fab417e97c.zip | |
prevent CNAME/PTR parsing from reading data past the response end
DNS parsing callbacks pass the response buffer end instead of the actual response end to dn_expand, so a malformed DNS response can use message compression to make dn_expand jump past the response end and attempt to parse uninitialized parts of that buffer, which might succeed and return garbage.
Diffstat (limited to 'src/network/lookup_name.c')
| -rw-r--r-- | src/network/lookup_name.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/src/network/lookup_name.c b/src/network/lookup_name.c index 5f6867cb..f268bcda 100644 --- a/src/network/lookup_name.c +++ b/src/network/lookup_name.c @@ -111,13 +111,13 @@ struct dpc_ctx { #define ABUF_SIZE 768 -static int dns_parse_callback(void *c, int rr, const void *data, int len, const void *packet) +static int dns_parse_callback(void *c, int rr, const void *data, int len, const void *packet, int plen) { char tmp[256]; int family; struct dpc_ctx *ctx = c; if (rr == RR_CNAME) { - if (__dn_expand(packet, (const unsigned char *)packet + ABUF_SIZE, + if (__dn_expand(packet, (const unsigned char *)packet + plen, data, tmp, sizeof tmp) > 0 && is_valid_hostname(tmp)) strcpy(ctx->canon, tmp); return 0; |