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| author | Alan Coopersmith <alan.coopersmith@oracle.com> | 2011-11-23 00:30:02 -0800 |
|---|---|---|
| committer | Alan Coopersmith <alan.coopersmith@oracle.com> | 2011-12-02 00:17:28 -0800 |
| commit | feebf6746374aa04b12e9e3e51313a3a82c03530 (patch) | |
| tree | 8da255bd06f88cca4d0d1e160dbb4355a046c553 | |
| parent | fb22a408c69a84f81905147de9e82cf66ffb6eb2 (diff) | |
Limit the number of screens Xvfb will attempt to allocate memory for
Commit f9e3a2955d2ca7 removing the MAXSCREEN limit left the screen
number too unlimited, and allowed any positive int for a screen number:
Xvfb :1 -screen 2147483647 1024x1024x8
Fatal server error:
Not enough memory for screen 2147483647
Found by Parfait 0.3.7:
Error: Integer overflow (CWE 190)
Integer parameter of memory allocation function realloc() may overflow due to multiplication with constant value 1112
at line 293 of hw/vfb/InitOutput.c in function 'ddxProcessArgument'.
Since the X11 connection setup only has a CARD8 for number of SCREENS,
limit to 255 screens, which is also low enough to avoid overflow on the
sizeof(*vfbScreens) * (screenNum + 1) calculation for realloc.
Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>
Reviewed-by: Jamey Sharp <jamey@minilop.net>
| -rw-r--r-- | hw/vfb/InitOutput.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/hw/vfb/InitOutput.c b/hw/vfb/InitOutput.c index 3e5d05100..9a9905d8f 100644 --- a/hw/vfb/InitOutput.c +++ b/hw/vfb/InitOutput.c @@ -280,7 +280,9 @@ ddxProcessArgument(int argc, char *argv[], int i) int screenNum; CHECK_FOR_REQUIRED_ARGUMENTS(2); screenNum = atoi(argv[i+1]); - if (screenNum < 0) + /* The protocol only has a CARD8 for number of screens in the + connection setup block, so don't allow more than that. */ + if ((screenNum < 0) || (screenNum >= 255)) { ErrorF("Invalid screen number %d\n", screenNum); UseMsg(); |