[ Upstream commit 281d464a34f540de166cee74b723e97ac2515ec3 ]
The devmap code allocates a number hash buckets equal to the next power
of two of the max_entries value provided when creating the map. When
rounding up to the next power of two, the 32-bit variable storing the
number of buckets can overflow, and the code checks for overflow by
checking if the truncated 32-bit value is equal to 0. However, on 32-bit
arches the rounding up itself can overflow mid-way through, because it
ends up doing a left-shift of 32 bits on an unsigned long value. If the
size of an unsigned long is four bytes, this is undefined behaviour, so
there is no guarantee that we'll end up with a nice and tidy 0-value at
the end.
Syzbot managed to turn this into a crash on arm32 by creating a
DEVMAP_HASH with max_entries > 0x80000000 and then trying to update it.
Fix this by moving the overflow check to before the rounding up
operation.
Fixes: 6f9d451ab1a3 ("xdp: Add devmap_hash map type for looking up devices by hashed index")
Link: https://lore.kernel.org/r/000000000000ed666a0611af6818@google.com
Reported-and-tested-by: syzbot+8cd36f6b65f3cafd400a@syzkaller.appspotmail.com
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Message-ID: <20240307120340.99577-2-toke@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Pu Lehui <pulehui@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This reverts commit 70294d8bc31f3b7789e5e32f757aa9344556d964 which is
commit 844f157f6c0a905d039d2e20212ab3231f2e5eaf upstream.
Commit 70294d8bc31f ("bpf: Eliminate rlimit-based memory accounting for
devmap maps") is part of the v5.11+ base mechanism of memcg-based memory
accounting[0]. The commit cannot be independently backported to the 5.10
stable branch, otherwise the related memory when creating devmap will be
unrestricted. Let's roll back to rlimit-based memory accounting mode for
devmap.
Link: https://lore.kernel.org/bpf/20201201215900.3569844-1-guro@fb.com [0]
Signed-off-by: Pu Lehui <pulehui@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This reverts commit 225da02acdc97af01b6bc6ce1a3e5362bf01d3fb which is
commit 281d464a34f540de166cee74b723e97ac2515ec3 upstream.
Commit 225da02acdc9 ("bpf: fix DEVMAP_HASH overflow check on 32-bit
architectures") relies on the v5.11+ base mechanism of memcg-based
memory accounting[0], which is not yet supported on the 5.10 stable
branch, so let's revert this commit in preparation for re-adapting it.
Link: https://lore.kernel.org/bpf/20201201215900.3569844-1-guro@fb.com [0]
Signed-off-by: Pu Lehui <pulehui@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 281d464a34f540de166cee74b723e97ac2515ec3 ]
The devmap code allocates a number hash buckets equal to the next power
of two of the max_entries value provided when creating the map. When
rounding up to the next power of two, the 32-bit variable storing the
number of buckets can overflow, and the code checks for overflow by
checking if the truncated 32-bit value is equal to 0. However, on 32-bit
arches the rounding up itself can overflow mid-way through, because it
ends up doing a left-shift of 32 bits on an unsigned long value. If the
size of an unsigned long is four bytes, this is undefined behaviour, so
there is no guarantee that we'll end up with a nice and tidy 0-value at
the end.
Syzbot managed to turn this into a crash on arm32 by creating a
DEVMAP_HASH with max_entries > 0x80000000 and then trying to update it.
Fix this by moving the overflow check to before the rounding up
operation.
Fixes: 6f9d451ab1a3 ("xdp: Add devmap_hash map type for looking up devices by hashed index")
Link: https://lore.kernel.org/r/000000000000ed666a0611af6818@google.com
Reported-and-tested-by: syzbot+8cd36f6b65f3cafd400a@syzkaller.appspotmail.com
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Message-ID: <20240307120340.99577-2-toke@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 844f157f6c0a905d039d2e20212ab3231f2e5eaf ]
Do not use rlimit-based memory accounting for devmap maps.
It has been replaced with the memcg-based memory accounting.
Signed-off-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20201201215900.3569844-23-guro@fb.com
Stable-dep-of: 281d464a34f5 ("bpf: Fix DEVMAP_HASH overflow check on 32-bit arches")
Signed-off-by: Sasha Levin <sashal@kernel.org>
