Gitweb:
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=5a021e9ffd56c22700133ebc37d607f95be8f7bd
Commit: 5a021e9ffd56c22700133ebc37d607f95be8f7bd
Parent: f745bb1c73e2395e6b9961d4d915a8f8e2cd32cd
Author: Matt Mackall <[EMAIL PROTECTED]>
AuthorDate: Thu Jul 19 11:30:14 2007 -0700
Committer: Linus Torvalds <[EMAIL PROTECTED]>
CommitDate: Thu Jul 19 14:21:04 2007 -0700
random: fix bound check ordering (CVE-2007-3105)
If root raised the default wakeup threshold over the size of the
output pool, the pool transfer function could overflow the stack with
RNG bytes, causing a DoS or potential privilege escalation.
(Bug reported by the PaX Team <[EMAIL PROTECTED]>)
Cc: Theodore Tso <[EMAIL PROTECTED]>
Cc: Willy Tarreau <[EMAIL PROTECTED]>
Signed-off-by: Matt Mackall <[EMAIL PROTECTED]>
Signed-off-by: Chris Wright <[EMAIL PROTECTED]>
Signed-off-by: Linus Torvalds <[EMAIL PROTECTED]>
---
drivers/char/random.c | 9 +++++++--
1 files changed, 7 insertions(+), 2 deletions(-)
diff --git a/drivers/char/random.c b/drivers/char/random.c
index 7f52712..397c714 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -693,9 +693,14 @@ static void xfer_secondary_pool(struct entropy_store *r,
size_t nbytes)
if (r->pull && r->entropy_count < nbytes * 8 &&
r->entropy_count < r->poolinfo->POOLBITS) {
- int bytes = max_t(int, random_read_wakeup_thresh / 8,
- min_t(int, nbytes, sizeof(tmp)));
+ /* If we're limited, always leave two wakeup worth's BITS */
int rsvd = r->limit ? 0 : random_read_wakeup_thresh/4;
+ int bytes = nbytes;
+
+ /* pull at least as many as BYTES as wakeup BITS */
+ bytes = max_t(int, bytes, random_read_wakeup_thresh / 8);
+ /* but never more than the buffer size */
+ bytes = min_t(int, bytes, sizeof(tmp));
DEBUG_ENT("going to reseed %s with %d bits "
"(%d of %d requested)\n",
-
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