pgsql: Fix potential pointer overflow in xlogreader.c.
Fix potential pointer overflow in xlogreader.c. While checking if a record could fit in the circular WAL decoding buffer, the coding from commit 3f1ce973 used arithmetic that could overflow. 64 bit systems were unaffected for various technical reasons, which probably explains the lack of problem reports. Likewise for 32 bit systems running known 32 bit kernels. The systems at risk of problems appear to be 32 bit processes running on 64 bit kernels, with unlucky placement in memory. Per complaint from GCC -fsanitize=undefined -m32, while testing variations of 039_end_of_wal.pl. Back-patch to 15. Reviewed-by: Nathan Bossart Reviewed-by: Robert Haas Discussion: https://postgr.es/m/CA%2BhUKGKH0oRPOX7DhiQ_b51sM8HqcPp2J3WA-Oen%3DdXog%2BAGGQ%40mail.gmail.com Branch -- REL_15_STABLE Details --- https://git.postgresql.org/pg/commitdiff/b9f687f5abaf40c13fed59fe08014116a8344102 Modified Files -- src/backend/access/transam/xlogreader.c | 46 ++--- 1 file changed, 37 insertions(+), 9 deletions(-)
pgsql: Fix potential pointer overflow in xlogreader.c.
Fix potential pointer overflow in xlogreader.c. While checking if a record could fit in the circular WAL decoding buffer, the coding from commit 3f1ce973 used arithmetic that could overflow. 64 bit systems were unaffected for various technical reasons, which probably explains the lack of problem reports. Likewise for 32 bit systems running known 32 bit kernels. The systems at risk of problems appear to be 32 bit processes running on 64 bit kernels, with unlucky placement in memory. Per complaint from GCC -fsanitize=undefined -m32, while testing variations of 039_end_of_wal.pl. Back-patch to 15. Reviewed-by: Nathan Bossart Reviewed-by: Robert Haas Discussion: https://postgr.es/m/CA%2BhUKGKH0oRPOX7DhiQ_b51sM8HqcPp2J3WA-Oen%3DdXog%2BAGGQ%40mail.gmail.com Branch -- master Details --- https://git.postgresql.org/pg/commitdiff/cd7f19da34684b7b12fdc08511c5ce7bebb09419 Modified Files -- src/backend/access/transam/xlogreader.c | 46 ++--- 1 file changed, 37 insertions(+), 9 deletions(-)
pgsql: Fix potential pointer overflow in xlogreader.c.
Fix potential pointer overflow in xlogreader.c. While checking if a record could fit in the circular WAL decoding buffer, the coding from commit 3f1ce973 used arithmetic that could overflow. 64 bit systems were unaffected for various technical reasons, which probably explains the lack of problem reports. Likewise for 32 bit systems running known 32 bit kernels. The systems at risk of problems appear to be 32 bit processes running on 64 bit kernels, with unlucky placement in memory. Per complaint from GCC -fsanitize=undefined -m32, while testing variations of 039_end_of_wal.pl. Back-patch to 15. Reviewed-by: Nathan Bossart Reviewed-by: Robert Haas Discussion: https://postgr.es/m/CA%2BhUKGKH0oRPOX7DhiQ_b51sM8HqcPp2J3WA-Oen%3DdXog%2BAGGQ%40mail.gmail.com Branch -- REL_16_STABLE Details --- https://git.postgresql.org/pg/commitdiff/8ca56620caffd6a1761eebd6a9498235321f222b Modified Files -- src/backend/access/transam/xlogreader.c | 46 ++--- 1 file changed, 37 insertions(+), 9 deletions(-)
