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authorBen Hutchings <ben@decadent.org.uk>2015-11-01 16:22:53 +0000
committerDavid S. Miller <davem@davemloft.net>2015-11-02 16:25:00 -0500
commit4ab42d78e37a294ac7bc56901d563c642e03c4ae (patch)
treeeed185aafd345a302f05711c3e6d5d80fca7c3f9 /drivers/net/slip
parent0baa57d8dc32db78369d8b5176ef56c5e2e18ab3 (diff)
downloadlinux-4ab42d78e37a294ac7bc56901d563c642e03c4ae.tar.bz2
ppp, slip: Validate VJ compression slot parameters completely
Currently slhc_init() treats out-of-range values of rslots and tslots as equivalent to 0, except that if tslots is too large it will dereference a null pointer (CVE-2015-7799). Add a range-check at the top of the function and make it return an ERR_PTR() on error instead of NULL. Change the callers accordingly. Compile-tested only. Reported-by: 郭永刚 <guoyonggang@360.cn> References: http://article.gmane.org/gmane.comp.security.oss.general/17908 Signed-off-by: Ben Hutchings <ben@decadent.org.uk> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/slip')
-rw-r--r--drivers/net/slip/slhc.c12
-rw-r--r--drivers/net/slip/slip.c2
2 files changed, 9 insertions, 5 deletions
diff --git a/drivers/net/slip/slhc.c b/drivers/net/slip/slhc.c
index 079f7adfcde5..27ed25252aac 100644
--- a/drivers/net/slip/slhc.c
+++ b/drivers/net/slip/slhc.c
@@ -84,8 +84,9 @@ static long decode(unsigned char **cpp);
static unsigned char * put16(unsigned char *cp, unsigned short x);
static unsigned short pull16(unsigned char **cpp);
-/* Initialize compression data structure
+/* Allocate compression data structure
* slots must be in range 0 to 255 (zero meaning no compression)
+ * Returns pointer to structure or ERR_PTR() on error.
*/
struct slcompress *
slhc_init(int rslots, int tslots)
@@ -94,11 +95,14 @@ slhc_init(int rslots, int tslots)
register struct cstate *ts;
struct slcompress *comp;
+ if (rslots < 0 || rslots > 255 || tslots < 0 || tslots > 255)
+ return ERR_PTR(-EINVAL);
+
comp = kzalloc(sizeof(struct slcompress), GFP_KERNEL);
if (! comp)
goto out_fail;
- if ( rslots > 0 && rslots < 256 ) {
+ if (rslots > 0) {
size_t rsize = rslots * sizeof(struct cstate);
comp->rstate = kzalloc(rsize, GFP_KERNEL);
if (! comp->rstate)
@@ -106,7 +110,7 @@ slhc_init(int rslots, int tslots)
comp->rslot_limit = rslots - 1;
}
- if ( tslots > 0 && tslots < 256 ) {
+ if (tslots > 0) {
size_t tsize = tslots * sizeof(struct cstate);
comp->tstate = kzalloc(tsize, GFP_KERNEL);
if (! comp->tstate)
@@ -141,7 +145,7 @@ out_free2:
out_free:
kfree(comp);
out_fail:
- return NULL;
+ return ERR_PTR(-ENOMEM);
}
diff --git a/drivers/net/slip/slip.c b/drivers/net/slip/slip.c
index 05387b1e2e95..a17d86a57734 100644
--- a/drivers/net/slip/slip.c
+++ b/drivers/net/slip/slip.c
@@ -164,7 +164,7 @@ static int sl_alloc_bufs(struct slip *sl, int mtu)
if (cbuff == NULL)
goto err_exit;
slcomp = slhc_init(16, 16);
- if (slcomp == NULL)
+ if (IS_ERR(slcomp))
goto err_exit;
#endif
spin_lock_bh(&sl->lock);