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| author | Phil Pennock <phil+git@pennock-tech.com> | 2020-10-29 21:48:05 -0400 |
|---|---|---|
| committer | Heiko Schlittermann (HS12-RIPE) <hs@schlittermann.de> | 2021-04-28 00:40:24 +0200 |
| commit | 3a54fcd1e303bf1cc49beca7ceac35d7448860a9 (patch) | |
| tree | a6e8d52d79d4208daac505a0085270edc38150a0 | |
| parent | a6e1f69d82adcfd3caab8f228d96750dfddc8f07 (diff) | |
| download | exim4-3a54fcd1e303bf1cc49beca7ceac35d7448860a9.tar.gz | |
SECURITY: Avoid integer overflow on too many recipients
(cherry picked from commit 323ff55e67b44e95f9d3cfaba155e385aa33c4bd)
| -rw-r--r-- | doc/doc-txt/ChangeLog | 5 | ||||
| -rw-r--r-- | src/src/receive.c | 7 |
2 files changed, 12 insertions, 0 deletions
diff --git a/doc/doc-txt/ChangeLog b/doc/doc-txt/ChangeLog index 055b1ace8..3bb5326ce 100644 --- a/doc/doc-txt/ChangeLog +++ b/doc/doc-txt/ChangeLog @@ -191,6 +191,11 @@ PP/07 Refuse to allocate too little memory, block negative/zero allocations. PP/08 Change default for recipients_max from unlimited to 50,000. +PP/09 Fix security issue with too many recipients on a message (to remove a + known security problem if someone does set recipients_max to unlimited, + or if local additions add to the recipient list). + Fixes CVE-2020-RCPTL reported by Qualys. + Exim version 4.94 ----------------- diff --git a/src/src/receive.c b/src/src/receive.c index ec90e93cd..ba6a8d3a6 100644 --- a/src/src/receive.c +++ b/src/src/receive.c @@ -485,11 +485,18 @@ Returns: nothing void receive_add_recipient(uschar *recipient, int pno) { +/* XXX This is a math limit; we should consider a performance/sanity limit too. */ +const int safe_recipients_limit = INT_MAX / sizeof(recipient_item) - 1; + if (recipients_count >= recipients_list_max) { recipient_item *oldlist = recipients_list; int oldmax = recipients_list_max; recipients_list_max = recipients_list_max ? 2*recipients_list_max : 50; + if ((recipients_list_max >= safe_recipients_limit) || (recipients_list_max < 0)) + { + log_write(0, LOG_MAIN|LOG_PANIC, "Too many recipients needed: %d not satisfiable", recipients_list_max); + } recipients_list = store_get(recipients_list_max * sizeof(recipient_item), FALSE); if (oldlist != NULL) memcpy(recipients_list, oldlist, oldmax * sizeof(recipient_item)); |