ghsa-wfpw-m32p-qqfp
Vulnerability from github
In the Linux kernel, the following vulnerability has been resolved:
smc: Fix various oops due to inet_sock type confusion.
syzbot reported weird splats [0][1] in cipso_v4_sock_setattr() while freeing inet_sk(sk)->inet_opt.
The address was freed multiple times even though it was read-only memory.
cipso_v4_sock_setattr() did nothing wrong, and the root cause was type confusion.
The cited commit made it possible to create smc_sock as an INET socket.
The issue is that struct smc_sock does not have struct inet_sock as the first member but hijacks AF_INET and AF_INET6 sk_family, which confuses various places.
In this case, inet_sock.inet_opt was actually smc_sock.clcsk_data_ready(), which is an address of a function in the text segment.
$ pahole -C inet_sock vmlinux struct inet_sock { ... struct ip_options_rcu * inet_opt; / 784 8 /
$ pahole -C smc_sock vmlinux struct smc_sock { ... void (clcsk_data_ready)(struct sock ); / 784 8 /
The same issue for another field was reported before. [2][3]
At that time, an ugly hack was suggested [4], but it makes both INET and SMC code error-prone and hard to change.
Also, yet another variant was fixed by a hacky commit 98d4435efcbf3 ("net/smc: prevent NULL pointer dereference in txopt_get").
Instead of papering over the root cause by such hacks, we should not allow non-INET socket to reuse the INET infra.
Let's add inet_sock as the first member of smc_sock.
[0]: kvfree_call_rcu(): Double-freed call. rcu_head 000000006921da73 WARNING: CPU: 0 PID: 6718 at mm/slab_common.c:1956 kvfree_call_rcu+0x94/0x3f0 mm/slab_common.c:1955 Modules linked in: CPU: 0 UID: 0 PID: 6718 Comm: syz.0.17 Tainted: G W 6.16.0-rc4-syzkaller-g7482bb149b9f #0 PREEMPT Tainted: [W]=WARN Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : kvfree_call_rcu+0x94/0x3f0 mm/slab_common.c:1955 lr : kvfree_call_rcu+0x94/0x3f0 mm/slab_common.c:1955 sp : ffff8000a03a7730 x29: ffff8000a03a7730 x28: 00000000fffffff5 x27: 1fffe000184823d3 x26: dfff800000000000 x25: ffff0000c2411e9e x24: ffff0000dd88da00 x23: ffff8000891ac9a0 x22: 00000000ffffffea x21: ffff8000891ac9a0 x20: ffff8000891ac9a0 x19: ffff80008afc2480 x18: 00000000ffffffff x17: 0000000000000000 x16: ffff80008ae642c8 x15: ffff700011ede14c x14: 1ffff00011ede14c x13: 0000000000000004 x12: ffffffffffffffff x11: ffff700011ede14c x10: 0000000000ff0100 x9 : 5fa3c1ffaf0ff000 x8 : 5fa3c1ffaf0ff000 x7 : 0000000000000001 x6 : 0000000000000001 x5 : ffff8000a03a7078 x4 : ffff80008f766c20 x3 : ffff80008054d360 x2 : 0000000000000000 x1 : 0000000000000201 x0 : 0000000000000000 Call trace: kvfree_call_rcu+0x94/0x3f0 mm/slab_common.c:1955 (P) cipso_v4_sock_setattr+0x2f0/0x3f4 net/ipv4/cipso_ipv4.c:1914 netlbl_sock_setattr+0x240/0x334 net/netlabel/netlabel_kapi.c:1000 smack_netlbl_add+0xa8/0x158 security/smack/smack_lsm.c:2581 smack_inode_setsecurity+0x378/0x430 security/smack/smack_lsm.c:2912 security_inode_setsecurity+0x118/0x3c0 security/security.c:2706 __vfs_setxattr_noperm+0x174/0x5c4 fs/xattr.c:251 __vfs_setxattr_locked+0x1ec/0x218 fs/xattr.c:295 vfs_setxattr+0x158/0x2ac fs/xattr.c:321 do_setxattr fs/xattr.c:636 [inline] file_setxattr+0x1b8/0x294 fs/xattr.c:646 path_setxattrat+0x2ac/0x320 fs/xattr.c:711 __do_sys_fsetxattr fs/xattr.c:761 [inline] __se_sys_fsetxattr fs/xattr.c:758 [inline] __arm64_sys_fsetxattr+0xc0/0xdc fs/xattr.c:758 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151 el0_svc+0x58/0x180 arch/arm64/kernel/entry-common.c:879 el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:898 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600
[ ---truncated---
{
"affected": [],
"aliases": [
"CVE-2025-38475"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-07-28T12:15:29Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nsmc: Fix various oops due to inet_sock type confusion.\n\nsyzbot reported weird splats [0][1] in cipso_v4_sock_setattr() while\nfreeing inet_sk(sk)-\u003einet_opt.\n\nThe address was freed multiple times even though it was read-only memory.\n\ncipso_v4_sock_setattr() did nothing wrong, and the root cause was type\nconfusion.\n\nThe cited commit made it possible to create smc_sock as an INET socket.\n\nThe issue is that struct smc_sock does not have struct inet_sock as the\nfirst member but hijacks AF_INET and AF_INET6 sk_family, which confuses\nvarious places.\n\nIn this case, inet_sock.inet_opt was actually smc_sock.clcsk_data_ready(),\nwhich is an address of a function in the text segment.\n\n $ pahole -C inet_sock vmlinux\n struct inet_sock {\n ...\n struct ip_options_rcu * inet_opt; /* 784 8 */\n\n $ pahole -C smc_sock vmlinux\n struct smc_sock {\n ...\n void (*clcsk_data_ready)(struct sock *); /* 784 8 */\n\nThe same issue for another field was reported before. [2][3]\n\nAt that time, an ugly hack was suggested [4], but it makes both INET\nand SMC code error-prone and hard to change.\n\nAlso, yet another variant was fixed by a hacky commit 98d4435efcbf3\n(\"net/smc: prevent NULL pointer dereference in txopt_get\").\n\nInstead of papering over the root cause by such hacks, we should not\nallow non-INET socket to reuse the INET infra.\n\nLet\u0027s add inet_sock as the first member of smc_sock.\n\n[0]:\nkvfree_call_rcu(): Double-freed call. rcu_head 000000006921da73\nWARNING: CPU: 0 PID: 6718 at mm/slab_common.c:1956 kvfree_call_rcu+0x94/0x3f0 mm/slab_common.c:1955\nModules linked in:\nCPU: 0 UID: 0 PID: 6718 Comm: syz.0.17 Tainted: G W 6.16.0-rc4-syzkaller-g7482bb149b9f #0 PREEMPT\nTainted: [W]=WARN\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025\npstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)\npc : kvfree_call_rcu+0x94/0x3f0 mm/slab_common.c:1955\nlr : kvfree_call_rcu+0x94/0x3f0 mm/slab_common.c:1955\nsp : ffff8000a03a7730\nx29: ffff8000a03a7730 x28: 00000000fffffff5 x27: 1fffe000184823d3\nx26: dfff800000000000 x25: ffff0000c2411e9e x24: ffff0000dd88da00\nx23: ffff8000891ac9a0 x22: 00000000ffffffea x21: ffff8000891ac9a0\nx20: ffff8000891ac9a0 x19: ffff80008afc2480 x18: 00000000ffffffff\nx17: 0000000000000000 x16: ffff80008ae642c8 x15: ffff700011ede14c\nx14: 1ffff00011ede14c x13: 0000000000000004 x12: ffffffffffffffff\nx11: ffff700011ede14c x10: 0000000000ff0100 x9 : 5fa3c1ffaf0ff000\nx8 : 5fa3c1ffaf0ff000 x7 : 0000000000000001 x6 : 0000000000000001\nx5 : ffff8000a03a7078 x4 : ffff80008f766c20 x3 : ffff80008054d360\nx2 : 0000000000000000 x1 : 0000000000000201 x0 : 0000000000000000\nCall trace:\n kvfree_call_rcu+0x94/0x3f0 mm/slab_common.c:1955 (P)\n cipso_v4_sock_setattr+0x2f0/0x3f4 net/ipv4/cipso_ipv4.c:1914\n netlbl_sock_setattr+0x240/0x334 net/netlabel/netlabel_kapi.c:1000\n smack_netlbl_add+0xa8/0x158 security/smack/smack_lsm.c:2581\n smack_inode_setsecurity+0x378/0x430 security/smack/smack_lsm.c:2912\n security_inode_setsecurity+0x118/0x3c0 security/security.c:2706\n __vfs_setxattr_noperm+0x174/0x5c4 fs/xattr.c:251\n __vfs_setxattr_locked+0x1ec/0x218 fs/xattr.c:295\n vfs_setxattr+0x158/0x2ac fs/xattr.c:321\n do_setxattr fs/xattr.c:636 [inline]\n file_setxattr+0x1b8/0x294 fs/xattr.c:646\n path_setxattrat+0x2ac/0x320 fs/xattr.c:711\n __do_sys_fsetxattr fs/xattr.c:761 [inline]\n __se_sys_fsetxattr fs/xattr.c:758 [inline]\n __arm64_sys_fsetxattr+0xc0/0xdc fs/xattr.c:758\n __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]\n invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49\n el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132\n do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151\n el0_svc+0x58/0x180 arch/arm64/kernel/entry-common.c:879\n el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:898\n el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600\n\n[\n---truncated---",
"id": "GHSA-wfpw-m32p-qqfp",
"modified": "2025-07-28T12:30:35Z",
"published": "2025-07-28T12:30:35Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-38475"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/5b02e397929e5b13b969ef1f8e43c7951e2864f5"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/60ada4fe644edaa6c2da97364184b0425e8aeaf5"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/67a167a6b8b45607bc34aa541d1c75097d18d460"
}
],
"schema_version": "1.4.0",
"severity": []
}
Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
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