tree c2954a70d2256ecc9d683481e95374ee4550aaca
parent 51128f86129a1257b59005356253f78411d77e95
author Willy Tarreau <w@1wt.eu> 1634821534 +0200
committer Willy Tarreau <w@1wt.eu> 1634913727 +0200
encoding latin1

BUG/MAJOR: buf: fix varint API post- vs pre- increment

A bogus test in b_get_varint(), b_put_varint(), b_peek_varint() shifts
the end of the buffer by one byte. Since the bug is the same in the read
and write functions, the buffer contents remain compatible, which explains
why this bug was not detected earlier. But if the buffer ends on an
aligned address or page, it can result in a one-byte overflow which will
typically cause a crash or an inconsistent behavior.

This API is only used by rings (e.g. for traces and boot messages) and
by DNS responses, so the probability to hit it is extremely low, but a
crash on boot was observed.

This must be backported to 2.2.

(cherry picked from commit dd362b7b24ea24d8f3c882dab1a69cf78af7cc90)
Signed-off-by: Willy Tarreau <w@1wt.eu>