[syzbot] [intel-wired-lan?] UBSAN: shift-out-of-bounds in e100_eeprom_load

[syzbot] [intel-wired-lan?] UBSAN: shift-out-of-bounds in e100_eeprom_load

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    848acc8ffe1b Merge tag 'fsverity-for-linus' of git://git.k..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=15087e32580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=145fa60d73086782
dashboard link: https://syzkaller.appspot.com/bug?extid=e0abb1d45ac291ebebeb
compiler:       gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=17ed13b9580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=162c5bb9580000

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-848acc8f.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/6fb497cc0c8d/vmlinux-848acc8f.xz
kernel image: https://storage.googleapis.com/syzbot-assets/663ccee34982/bzImage-848acc8f.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+e0abb1d45ac291ebebeb@syzkaller.appspotmail.com

e1000e 0000:00:02.0 eth1: removed PHC
e1000e 0000:00:02.0 eth1: NIC Link is Down
------------[ cut here ]------------
UBSAN: shift-out-of-bounds in drivers/net/ethernet/intel/e100.c:768:21
shift exponent 65529 is too large for 32-bit type 'int'
CPU: 0 UID: 0 PID: 5934 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
 ubsan_epilogue+0xa/0x30 lib/ubsan.c:233
 __ubsan_handle_shift_out_of_bounds+0x279/0x2a0 lib/ubsan.c:494
 e100_eeprom_load.cold+0x55/0x9e drivers/net/ethernet/intel/e100.c:768
 e100_probe+0xd07/0x1ab0 drivers/net/ethernet/intel/e100.c:2921
 local_pci_probe+0xdd/0x1b0 drivers/pci/pci-driver.c:332
 pci_call_probe+0x176/0x800 drivers/pci/pci-driver.c:394
 __pci_device_probe drivers/pci/pci-driver.c:455 [inline]
 pci_device_probe+0x1cd/0x370 drivers/pci/pci-driver.c:489
 call_driver_probe drivers/base/dd.c:628 [inline]
 really_probe+0x241/0xa60 drivers/base/dd.c:706
 __driver_probe_device+0x20e/0x450 drivers/base/dd.c:868
 device_driver_attach+0xd1/0x220 drivers/base/dd.c:1203
 bind_store+0xf4/0x190 drivers/base/bus.c:267
 drv_attr_store+0x74/0xb0 drivers/base/bus.c:125
 sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:145
 kernfs_fop_write_iter+0x3e0/0x5f0 fs/kernfs/file.c:345
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x6ac/0x1050 fs/read_write.c:687
 ksys_write+0x12a/0x250 fs/read_write.c:739
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f60d819e019
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffc13c52ae8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f60d8425fa0 RCX: 00007f60d819e019
RDX: 000000000000000c RSI: 0000200000000280 RDI: 0000000000000005
RBP: 00007f60d823500c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f60d8425fac R14: 00007f60d8425fa0 R15: 00007f60d8425fa0
 </TASK>
---[ end trace ]---


---
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Forwarded: [PATCH] e100: prevent shift out-of-bounds in e100_eeprom_load

[syzbot]

For archival purposes, forwarding an incoming command email to
linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com.

***

Subject: [PATCH] e100: prevent shift out-of-bounds in e100_eeprom_load
Author: pavankumaryalagada@gmail.com

From: Yalagada Pavan Kumar <pavankumaryalagada@gmail.com>

When reading the EEPROM address length, e100_eeprom_read() can return
an invalid length (0 or >= 16). Passing an invalid addr_len to bit-shift
operations causes a shift out-of-bounds, triggering a kernel panic or
UBSAN warning.

Validate addr_len after reading it from EEPROM and return -EINVAL if
the value is out of bounds. Additionally, use 1U to prevent
signed integer overflow when calculating eeprom_wc.

Reported-by: syzbot+e0abb1d45ac291ebebeb@syzkaller.appspotmail.com
Link: https://syzkaller.appspot.com/bug?extid=e0abb1d45ac291ebebeb
Signed-off-by: Yalagada Pavan Kumar <pavankumaryalagada@gmail.com>
#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
---
Tested using syzbot c reproducer.
#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
---
 drivers/net/ethernet/intel/e100.c | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/intel/e100.c b/drivers/net/ethernet/intel/e100.c
index 29960762e64a..1de5cd41ea0c 100644
--- a/drivers/net/ethernet/intel/e100.c
+++ b/drivers/net/ethernet/intel/e100.c
@@ -744,7 +744,12 @@ static __le16 e100_eeprom_read(struct nic *nic, u16 *addr_len, u16 addr)
 		 * complete address.  Use this to adjust addr_len. */
 		ctrl = ioread8(&nic->csr->eeprom_ctrl_lo);
 		if (!(ctrl & eedo) && i > 16) {
-			*addr_len -= (i - 16);
+			u16 len = i - 16;
+
+			if (len > *addr_len)
+				*addr_len = 0;
+			else
+				*addr_len -= len;
 			i = 17;
 		}
 
@@ -765,7 +770,15 @@ static int e100_eeprom_load(struct nic *nic)
 
 	/* Try reading with an 8-bit addr len to discover actual addr len */
 	e100_eeprom_read(nic, &addr_len, 0);
-	nic->eeprom_wc = 1 << addr_len;
+
+	if (!addr_len || addr_len >= 16) {
+		netif_err(nic, probe, nic->netdev,
+			"Invalid EEPROM address length %u\n",
+			addr_len);
+		return -EINVAL;
+	}
+
+	nic->eeprom_wc = 1U << addr_len;
 
 	for (addr = 0; addr < nic->eeprom_wc; addr++) {
 		nic->eeprom[addr] = e100_eeprom_read(nic, &addr_len, addr);
-- 
2.43.0

Forwarded: [PATCH net] e100: fix shift-out-of-bounds in e100_eeprom_load()

[syzbot]

For archival purposes, forwarding an incoming command email to
linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com.

***

Subject: [PATCH net] e100: fix shift-out-of-bounds in e100_eeprom_load()
Author: malathi.a2000@gmail.com

#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git f9a2394a23482bfd330911e9c8295b71724feacd

e100_eeprom_load() and e100_eeprom_save() start with an address length
of 8 and call e100_eeprom_read() to auto-detect the real EEPROM address
length. e100_eeprom_read() adjusts the length with

	*addr_len -= (i - 16);

based on when the EEPROM drives a dummy zero onto EEDO. A malfunctioning
or emulated device that drives EEDO low too early makes (i - 16) exceed
the current length, underflowing the u16 addr_len to a large value such
as 65529.

That value is then used as a shift count:

	nic->eeprom_wc = 1 << addr_len;

which is undefined behaviour and additionally overflows the fixed-size
nic->eeprom[256] cache.

  UBSAN: shift-out-of-bounds in drivers/net/ethernet/intel/e100.c:768:21
  shift exponent 65529 is too large for 32-bit type 'int'

The EEPROM cache holds at most 256 words, so a valid address length is
never larger than 8. Reject larger values before using addr_len.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Reported-by: syzbot+e0abb1d45ac291ebebeb@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=e0abb1d45ac291ebebeb
Signed-off-by: Malathi <malathi.a2000@gmail.com>
---
 drivers/net/ethernet/intel/e100.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/net/ethernet/intel/e100.c b/drivers/net/ethernet/intel/e100.c
index 29960762e64a..a236273f5e65 100644
--- a/drivers/net/ethernet/intel/e100.c
+++ b/drivers/net/ethernet/intel/e100.c
@@ -765,6 +765,11 @@ static int e100_eeprom_load(struct nic *nic)
 
 	/* Try reading with an 8-bit addr len to discover actual addr len */
 	e100_eeprom_read(nic, &addr_len, 0);
+	if (addr_len > 8) {
+		netif_err(nic, probe, nic->netdev,
+			  "invalid EEPROM address length %u\n", addr_len);
+		return -EINVAL;
+	}
 	nic->eeprom_wc = 1 << addr_len;
 
 	for (addr = 0; addr < nic->eeprom_wc; addr++) {
@@ -791,6 +796,11 @@ static int e100_eeprom_save(struct nic *nic, u16 start, u16 count)
 
 	/* Try reading with an 8-bit addr len to discover actual addr len */
 	e100_eeprom_read(nic, &addr_len, 0);
+	if (addr_len > 8) {
+		netif_err(nic, probe, nic->netdev,
+			  "invalid EEPROM address length %u\n", addr_len);
+		return -EINVAL;
+	}
 	nic->eeprom_wc = 1 << addr_len;
 
 	if (start + count >= nic->eeprom_wc)
-- 
2.43.0