Messages in this thread Patch in this message | | | Date | Mon, 23 Feb 2015 18:44:19 +0300 | From | Dan Carpenter <> | Subject | [patch] groups: integer underflow in groups_alloc() |
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This is called from rsc_parse() with a use controlled value. Say for example that "gidsetsize" is negative, then we could end up allocating less than sizeof(struct group_info) leading to memory corruption.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> --- I copied the NGROUPS_MAX limit from the surrounding code, I'm not absolutely that it's the correct limit to use.
diff --git a/kernel/groups.c b/kernel/groups.c index 664411f..e9341b3 100644 --- a/kernel/groups.c +++ b/kernel/groups.c @@ -18,6 +18,9 @@ struct group_info *groups_alloc(int gidsetsize) int nblocks; int i; + if ((unsigned)gidsetsize > NGROUPS_MAX) + return NULL; + nblocks = (gidsetsize + NGROUPS_PER_BLOCK - 1) / NGROUPS_PER_BLOCK; /* Make sure we always allocate at least one indirect block pointer */ nblocks = nblocks ? : 1;
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