| Message ID | 20240630-bond-oob-v5-1-7d7996e0a077@kernel.org (mailing list archive) |
|---|---|
| State | Changes Requested |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net,v5] bonding: Fix out-of-bounds read in bond_option_arp_ip_targets_set() | expand |
'Simon Horman' <horms@kernel.org> wrote: >From: Sam Sun <samsun1006219@gmail.com> > >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> >--- >Changes in v5 (Simon): >- Remove stray 'I4' from netdev_err() string. Thanks to Hangbin Liu. >- Sorry for the long delay between v4 and v5, this completely slipped my > mind. >- Link to v4: https://lore.kernel.org/r/20240419-bond-oob-v4-1-69dd1a66db20@kernel.org > >Changes in v4 (Simon): >- Correct whitespace mangled patch; posting as requested by Sam Sun >- Link to v3: https://lore.kernel.org/r/CAEkJfYOnsLLiCrtgOpq2Upr+_W0dViYVHU8YdjJOi-mxD8H9oQ@mail.gmail.com > >Changes in v3 (Sam Sun): >- According to Hangbin's opinion, change Fixes tag from 4fb0ef585eb2 > ("bonding: convert arp_ip_target to use the new option API") to > f9de11a16594 ("bonding: add ip checks when store ip target"). >- Link to v2: https://lore.kernel.org/r/CAEkJfYMdDQKY1C-wBZLiaJ=dCqfM9r=rykwwf+J-XHsFp7D9Ag@mail.gmail.com/ > >Changes in v2 (Sam Sun): >- According to Jay and Hangbin's opinion, remove target address in > netdev_err message since target is not initialized in error path and > will not provide useful information. >- Link to v1: https://lore.kernel.org/r/CAEkJfYPYF-nNB2oiXfXwjPG0VVB2Bd8Q8kAq+74J=R+4HkngWw@mail.gmail.com/ >--- > 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 0cacd7027e35..228128e727c2 100644 >--- a/drivers/net/bonding/bond_options.c >+++ b/drivers/net/bonding/bond_options.c >@@ -1214,9 +1214,9 @@ 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)) || >+ !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] == '+') >
On Sun, Jun 30, 2024 at 02:20:55PM +0100, 'Simon Horman' wrote: > From: Sam Sun <samsun1006219@gmail.com> > > 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> Reviewed-by: Hangbin Liu <liuhangbin@gmail.com>
On Sun, 30 Jun 2024 14:20:55 +0100 'Simon Horman' wrote:
> + if (!(strlen(newval->string)) ||
The extra brackets made me look, this really feels like it wants to be
written as:
if (!newval->string[0] ||
or:
if (strlen(newval->string) < 1 ||
Jakub Kicinski <kuba@kernel.org> wrote: >On Sun, 30 Jun 2024 14:20:55 +0100 'Simon Horman' wrote: >> + if (!(strlen(newval->string)) || > >The extra brackets made me look, this really feels like it wants to be >written as: > > if (!newval->string[0] || > >or: > > if (strlen(newval->string) < 1 || I find the second option clearer, FWIW. This isn't in a hot path, and including strlen() in there makes it more obvious to my reading what the intent is. The size_t return from strlen() is unsigned, so we really want to test the return value for zero-ness. -J --- -Jay Vosburgh, jay.vosburgh@canonical.com
On Mon, 01 Jul 2024 16:07:46 -0700 Jay Vosburgh wrote: > > if (strlen(newval->string) < 1 || > > I find the second option clearer, FWIW. This isn't in a hot > path, and including strlen() in there makes it more obvious to my > reading what the intent is. The size_t return from strlen() is > unsigned, so we really want to test the return value for zero-ness. True, I picked < 1 because the line below offsets by 1. Either way is fine, but lets make sure we drop the parenthesis.
On Mon, Jul 01, 2024 at 07:59:08PM -0700, Jakub Kicinski wrote: > On Mon, 01 Jul 2024 16:07:46 -0700 Jay Vosburgh wrote: > > > if (strlen(newval->string) < 1 || > > > > I find the second option clearer, FWIW. This isn't in a hot > > path, and including strlen() in there makes it more obvious to my > > reading what the intent is. The size_t return from strlen() is > > unsigned, so we really want to test the return value for zero-ness. > > True, I picked < 1 because the line below offsets by 1. > Either way is fine, but lets make sure we drop the parenthesis. Thanks, I will go with < 1.
diff --git a/drivers/net/bonding/bond_options.c b/drivers/net/bonding/bond_options.c index 0cacd7027e35..228128e727c2 100644 --- a/drivers/net/bonding/bond_options.c +++ b/drivers/net/bonding/bond_options.c @@ -1214,9 +1214,9 @@ 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)) || + !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] == '+')