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authorAlan Coopersmith <alan.coopersmith@oracle.com>2014-01-22 23:12:04 -0800
committerMike Gabriel <mike.gabriel@das-netzwerkteam.de>2015-02-14 16:14:32 +0100
commit985ca320f841bd9a3efc484f92436b3d65ec1b31 (patch)
tree64ec53aa1272c0888b3b19f3efaae8e4471bd3f0 /nx-X11/programs/Xserver/dbe
parent82d7279ebfa04f319e68145b3adbf65716e59584 (diff)
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dbe: unvalidated lengths in DbeSwapBuffers calls [CVE-2014-8097]
ProcDbeSwapBuffers() has a 32bit (n) length value that it uses to read from a buffer. The length is never validated, which can lead to out of bound reads, and possibly returning the data read from out of bounds to the misbehaving client via an X Error packet. SProcDbeSwapBuffers() swaps data (for correct endianness) before handing it off to the real proc. While doing the swapping, the length field is not validated, which can cause memory corruption. v2: reorder checks to avoid compilers optimizing out checks for overflow that happen after we'd already have done the overflowing multiplications. v3: backport to nx-libs 3.6.x (Mike DePaulo) Reported-by: Ilja Van Sprundel <ivansprundel@ioactive.com> Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com> Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net> Conflicts: dbe/dbe.c
Diffstat (limited to 'nx-X11/programs/Xserver/dbe')
-rw-r--r--nx-X11/programs/Xserver/dbe/dbe.c11
1 files changed, 8 insertions, 3 deletions
diff --git a/nx-X11/programs/Xserver/dbe/dbe.c b/nx-X11/programs/Xserver/dbe/dbe.c
index c0d6131b7..5a1e9b00b 100644
--- a/nx-X11/programs/Xserver/dbe/dbe.c
+++ b/nx-X11/programs/Xserver/dbe/dbe.c
@@ -725,8 +725,8 @@ ProcDbeSwapBuffers(client)
DbeSwapInfoPtr swapInfo;
xDbeSwapInfo *dbeSwapInfo;
int error;
- register int i, j;
- int nStuff;
+ unsigned int i, j;
+ unsigned int nStuff;
REQUEST_AT_LEAST_SIZE(xDbeSwapBuffersReq);
@@ -734,11 +734,13 @@ ProcDbeSwapBuffers(client)
if (nStuff == 0)
{
+ REQUEST_SIZE_MATCH(xDbeSwapBuffersReq);
return(Success);
}
if (nStuff > UINT32_MAX / sizeof(DbeSwapInfoRec))
return BadAlloc;
+ REQUEST_FIXED_SIZE(xDbeSwapBuffersReq, nStuff * sizeof(xDbeSwapInfo));
/* Get to the swap info appended to the end of the request. */
dbeSwapInfo = (xDbeSwapInfo *)&stuff[1];
@@ -1289,7 +1291,7 @@ SProcDbeSwapBuffers(client)
ClientPtr client;
{
REQUEST(xDbeSwapBuffersReq);
- register int i, n;
+ unsigned int i, n;
xDbeSwapInfo *pSwapInfo;
@@ -1297,6 +1299,9 @@ SProcDbeSwapBuffers(client)
REQUEST_AT_LEAST_SIZE(xDbeSwapBuffersReq);
swapl(&stuff->n, n);
+ if (stuff->n > UINT32_MAX / sizeof(DbeSwapInfoRec))
+ return BadAlloc;
+ REQUEST_FIXED_SIZE(xDbeSwapBuffersReq, stuff->n * sizeof(xDbeSwapInfo));
if (stuff->n != 0)
{