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authorBjörn-Egil Dahlberg <egil@erlang.org>2015-01-29 16:04:46 +0100
committerBjörn-Egil Dahlberg <egil@erlang.org>2015-01-29 16:04:46 +0100
commit4d960f16d89c880507c951e1c74ac17e349f5dd6 (patch)
treee5006ab87aeade36b216d8a77425d443c2feed76
parentaf87b1c3d4897840d8247589a88d3611106ecedc (diff)
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erts: Fix getifaddrs realloc ptr mismatch
When a buffer was exhausted and subsequently a realloc, we could get an invalid pointer. For this to occur we would need to have a realloc to lower adresses. The symptom would be garbage returned from erlang:port_control(Port, 25, []) (prim_inet:getifaddrs(Port) resulting in a badarg) or a segmentation fault.
-rw-r--r--erts/emulator/drivers/common/inet_drv.c53
1 files changed, 45 insertions, 8 deletions
diff --git a/erts/emulator/drivers/common/inet_drv.c b/erts/emulator/drivers/common/inet_drv.c
index db8a251fdd..ff155cc07c 100644
--- a/erts/emulator/drivers/common/inet_drv.c
+++ b/erts/emulator/drivers/common/inet_drv.c
@@ -4721,6 +4721,36 @@ static char* sockaddr_to_buf(struct sockaddr* addr, char* ptr, char* end)
return NULL;
}
+/* sockaddr_bufsz_need
+ * Returns the number of bytes needed to store the information
+ * through sockaddr_to_buf
+ */
+
+static size_t sockaddr_bufsz_need(struct sockaddr* addr)
+{
+ if (addr->sa_family == AF_INET || addr->sa_family == 0) {
+ return 1 + sizeof(struct in_addr);
+ }
+#if defined(HAVE_IN6) && defined(AF_INET6)
+ else if (addr->sa_family == AF_INET6) {
+ return 1 + sizeof(struct in6_addr);
+ }
+#endif
+#if defined(AF_LINK)
+ if (addr->sa_family == AF_LINK) {
+ struct sockaddr_dl *sdl_p = (struct sockaddr_dl*) addr;
+ return 2 + sdl_p->sdl_alen;
+ }
+#endif
+#if defined(AF_PACKET) && defined(HAVE_NETPACKET_PACKET_H)
+ else if(addr->sa_family == AF_PACKET) {
+ struct sockaddr_ll *sll_p = (struct sockaddr_ll*) addr;
+ return 2 + sll_p->sll_halen;
+ }
+#endif
+ return 0;
+}
+
static char* buf_to_sockaddr(char* ptr, char* end, struct sockaddr* addr)
{
buf_check(ptr,end,1);
@@ -5799,6 +5829,11 @@ done:
}
#elif defined(HAVE_GETIFADDRS)
+#ifdef DEBUG
+#define GETIFADDRS_BUFSZ (1)
+#else
+#define GETIFADDRS_BUFSZ (512)
+#endif
static ErlDrvSSizeT inet_ctl_getifaddrs(inet_descriptor* desc_p,
char **rbuf_pp, ErlDrvSizeT rsize)
@@ -5809,15 +5844,15 @@ static ErlDrvSSizeT inet_ctl_getifaddrs(inet_descriptor* desc_p,
char *buf_p;
char *buf_alloc_p;
- buf_size = 512;
- buf_alloc_p = ALLOC(buf_size);
+ buf_size = GETIFADDRS_BUFSZ;
+ buf_alloc_p = ALLOC(GETIFADDRS_BUFSZ);
buf_p = buf_alloc_p;
# define BUF_ENSURE(Size) \
do { \
int NEED_, GOT_ = buf_p - buf_alloc_p; \
NEED_ = GOT_ + (Size); \
if (NEED_ > buf_size) { \
- buf_size = NEED_ + 512; \
+ buf_size = NEED_ + GETIFADDRS_BUFSZ; \
buf_alloc_p = REALLOC(buf_alloc_p, buf_size); \
buf_p = buf_alloc_p + GOT_; \
} \
@@ -5830,7 +5865,7 @@ static ErlDrvSSizeT inet_ctl_getifaddrs(inet_descriptor* desc_p,
while (! (P_ = sockaddr_to_buf((sa), buf_p, \
buf_alloc_p+buf_size))) { \
int GOT_ = buf_p - buf_alloc_p; \
- buf_size += 512; \
+ buf_size += GETIFADDRS_BUFSZ; \
buf_alloc_p = REALLOC(buf_alloc_p, buf_size); \
buf_p = buf_alloc_p + GOT_; \
} \
@@ -5887,10 +5922,11 @@ static ErlDrvSSizeT inet_ctl_getifaddrs(inet_descriptor* desc_p,
|| ifa_p->ifa_addr->sa_family == AF_PACKET
#endif
) {
- char *bp = buf_p;
- BUF_ENSURE(1);
- SOCKADDR_TO_BUF(INET_IFOPT_HWADDR, ifa_p->ifa_addr);
- if (buf_p - bp < 4) buf_p = bp; /* Empty hwaddr */
+ size_t need = sockaddr_bufsz_need(ifa_p->ifa_addr);
+ if (need > 3) {
+ BUF_ENSURE(1 + need);
+ SOCKADDR_TO_BUF(INET_IFOPT_HWADDR, ifa_p->ifa_addr);
+ }
}
#endif
}
@@ -5905,6 +5941,7 @@ static ErlDrvSSizeT inet_ctl_getifaddrs(inet_descriptor* desc_p,
return buf_size;
# undef BUF_ENSURE
}
+#undef GETIFADDRS_BUFSZ
#else