5.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Sam Sun samsun1006219@gmail.com
[ Upstream commit e271ff53807e8f2c628758290f0e499dbe51cb3d ]
In function bond_option_arp_ip_targets_set(), if newval->string is an empty string, newval->string+1 will point to the byte after the string, causing an out-of-bound read.
BUG: KASAN: slab-out-of-bounds in strlen+0x7d/0xa0 lib/string.c:418 Read of size 1 at addr ffff8881119c4781 by task syz-executor665/8107 CPU: 1 PID: 8107 Comm: syz-executor665 Not tainted 6.7.0-rc7 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd9/0x150 lib/dump_stack.c:106 print_address_description mm/kasan/report.c:364 [inline] print_report+0xc1/0x5e0 mm/kasan/report.c:475 kasan_report+0xbe/0xf0 mm/kasan/report.c:588 strlen+0x7d/0xa0 lib/string.c:418 __fortify_strlen include/linux/fortify-string.h:210 [inline] in4_pton+0xa3/0x3f0 net/core/utils.c:130 bond_option_arp_ip_targets_set+0xc2/0x910 drivers/net/bonding/bond_options.c:1201 __bond_opt_set+0x2a4/0x1030 drivers/net/bonding/bond_options.c:767 __bond_opt_set_notify+0x48/0x150 drivers/net/bonding/bond_options.c:792 bond_opt_tryset_rtnl+0xda/0x160 drivers/net/bonding/bond_options.c:817 bonding_sysfs_store_option+0xa1/0x120 drivers/net/bonding/bond_sysfs.c:156 dev_attr_store+0x54/0x80 drivers/base/core.c:2366 sysfs_kf_write+0x114/0x170 fs/sysfs/file.c:136 kernfs_fop_write_iter+0x337/0x500 fs/kernfs/file.c:334 call_write_iter include/linux/fs.h:2020 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x96a/0xd80 fs/read_write.c:584 ksys_write+0x122/0x250 fs/read_write.c:637 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0x40/0x110 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x63/0x6b ---[ end trace ]---
Fix it by adding a check of string length before using it.
Fixes: f9de11a16594 ("bonding: add ip checks when store ip target") Signed-off-by: Yue Sun samsun1006219@gmail.com Signed-off-by: Simon Horman horms@kernel.org Acked-by: Jay Vosburgh jay.vosburgh@canonical.com Reviewed-by: Hangbin Liu liuhangbin@gmail.com Link: https://patch.msgid.link/20240702-bond-oob-v6-1-2dfdba195c19@kernel.org Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/bonding/bond_options.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/net/bonding/bond_options.c b/drivers/net/bonding/bond_options.c index 933087d85549a..68fa3e891e6f2 100644 --- a/drivers/net/bonding/bond_options.c +++ b/drivers/net/bonding/bond_options.c @@ -1084,9 +1084,9 @@ static int bond_option_arp_ip_targets_set(struct bonding *bond, __be32 target;
if (newval->string) { - if (!in4_pton(newval->string+1, -1, (u8 *)&target, -1, NULL)) { - netdev_err(bond->dev, "invalid ARP target %pI4 specified\n", - &target); + if (strlen(newval->string) < 1 || + !in4_pton(newval->string + 1, -1, (u8 *)&target, -1, NULL)) { + netdev_err(bond->dev, "invalid ARP target specified\n"); return ret; } if (newval->string[0] == '+')