5.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Pablo Neira Ayuso pablo@netfilter.org
[ Upstream commit 542ed8145e6f9392e3d0a86a0e9027d2ffd183e4 ]
Access to genmask field in struct nft_set_ext results in unaligned atomic read:
[ 72.130109] Unable to handle kernel paging request at virtual address ffff0000c2bb708c [ 72.131036] Mem abort info: [ 72.131213] ESR = 0x0000000096000021 [ 72.131446] EC = 0x25: DABT (current EL), IL = 32 bits [ 72.132209] SET = 0, FnV = 0 [ 72.133216] EA = 0, S1PTW = 0 [ 72.134080] FSC = 0x21: alignment fault [ 72.135593] Data abort info: [ 72.137194] ISV = 0, ISS = 0x00000021, ISS2 = 0x00000000 [ 72.142351] CM = 0, WnR = 0, TnD = 0, TagAccess = 0 [ 72.145989] GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0 [ 72.150115] swapper pgtable: 4k pages, 48-bit VAs, pgdp=0000000237d27000 [ 72.154893] [ffff0000c2bb708c] pgd=0000000000000000, p4d=180000023ffff403, pud=180000023f84b403, pmd=180000023f835403, +pte=0068000102bb7707 [ 72.163021] Internal error: Oops: 0000000096000021 [#1] SMP [...] [ 72.170041] CPU: 7 UID: 0 PID: 54 Comm: kworker/7:0 Tainted: G E 6.13.0-rc3+ #2 [ 72.170509] Tainted: [E]=UNSIGNED_MODULE [ 72.170720] Hardware name: QEMU QEMU Virtual Machine, BIOS edk2-stable202302-for-qemu 03/01/2023 [ 72.171192] Workqueue: events_power_efficient nft_rhash_gc [nf_tables] [ 72.171552] pstate: 21400005 (nzCv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--) [ 72.171915] pc : nft_rhash_gc+0x200/0x2d8 [nf_tables] [ 72.172166] lr : nft_rhash_gc+0x128/0x2d8 [nf_tables] [ 72.172546] sp : ffff800081f2bce0 [ 72.172724] x29: ffff800081f2bd40 x28: ffff0000c2bb708c x27: 0000000000000038 [ 72.173078] x26: ffff0000c6780ef0 x25: ffff0000c643df00 x24: ffff0000c6778f78 [ 72.173431] x23: 000000000000001a x22: ffff0000c4b1f000 x21: ffff0000c6780f78 [ 72.173782] x20: ffff0000c2bb70dc x19: ffff0000c2bb7080 x18: 0000000000000000 [ 72.174135] x17: ffff0000c0a4e1c0 x16: 0000000000003000 x15: 0000ac26d173b978 [ 72.174485] x14: ffffffffffffffff x13: 0000000000000030 x12: ffff0000c6780ef0 [ 72.174841] x11: 0000000000000000 x10: ffff800081f2bcf8 x9 : ffff0000c3000000 [ 72.175193] x8 : 00000000000004be x7 : 0000000000000000 x6 : 0000000000000000 [ 72.175544] x5 : 0000000000000040 x4 : ffff0000c3000010 x3 : 0000000000000000 [ 72.175871] x2 : 0000000000003a98 x1 : ffff0000c2bb708c x0 : 0000000000000004 [ 72.176207] Call trace: [ 72.176316] nft_rhash_gc+0x200/0x2d8 [nf_tables] (P) [ 72.176653] process_one_work+0x178/0x3d0 [ 72.176831] worker_thread+0x200/0x3f0 [ 72.176995] kthread+0xe8/0xf8 [ 72.177130] ret_from_fork+0x10/0x20 [ 72.177289] Code: 54fff984 d503201f d2800080 91003261 (f820303f) [ 72.177557] ---[ end trace 0000000000000000 ]---
Align struct nft_set_ext to word size to address this and documentation it.
pahole reports that this increases the size of elements for rhash and pipapo in 8 bytes on x86_64.
Fixes: 7ffc7481153b ("netfilter: nft_set_hash: skip duplicated elements pending gc run") Signed-off-by: Pablo Neira Ayuso pablo@netfilter.org Signed-off-by: Sasha Levin sashal@kernel.org --- include/net/netfilter/nf_tables.h | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/include/net/netfilter/nf_tables.h b/include/net/netfilter/nf_tables.h index c50dee30a70c..92551a765a44 100644 --- a/include/net/netfilter/nf_tables.h +++ b/include/net/netfilter/nf_tables.h @@ -571,15 +571,18 @@ struct nft_set_ext_tmpl { /** * struct nft_set_ext - set extensions * - * @genmask: generation mask + * @genmask: generation mask, but also flags (see NFT_SET_ELEM_DEAD_BIT) * @offset: offsets of individual extension types * @data: beginning of extension data + * + * This structure must be aligned to word size, otherwise atomic bitops + * on genmask field can cause alignment failure on some archs. */ struct nft_set_ext { u8 genmask; u8 offset[NFT_SET_EXT_NUM]; char data[]; -}; +} __aligned(BITS_PER_LONG / 8);
static inline void nft_set_ext_prepare(struct nft_set_ext_tmpl *tmpl) {