proc: fix UAF in proc_get_inode()
In the Linux kernel, the following vulnerability has been resolved: proc: fix UAF in proc_get_inode() Fix race between rmmod and /proc/XXX's inode instantiation. The bug is that pde->proc_ops don't belong to /proc, it belongs to a module, therefore dereferencing it after /proc entry has been registered is a bug unless use_pde/unuse_pde() pair has been used. use_pde/unuse_pde can be avoided (2 atomic ops!) because pde->proc_ops never changes so information necessary for inode instantiation can be saved _before_ proc_register() in PDE itself and used later, avoiding pde->proc_ops->... dereference. rmmod lookup sys_delete_module proc_lookup_de pde_get(de); proc_get_inode(dir->i_sb, de); mod->exit() proc_remove remove_proc_subtree proc_entry_rundown(de); free_module(mod); if (S_ISREG(inode->i_mode)) if (de->proc_ops->proc_read_iter) --> As module is already freed, will trigger UAF BUG: unable to handle page fault for address: fffffbfff80a702b PGD 817fc4067 P4D 817fc4067 PUD 817fc0067 PMD 102ef4067 PTE 0 Oops: Oops: 0000 [#1] PREEMPT SMP KASAN PTI CPU: 26 UID: 0 PID: 2667 Comm: ls Tainted: G Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) RIP: 0010:proc_get_inode+0x302/0x6e0 RSP: 0018:ffff88811c837998 EFLAGS: 00010a06 RAX: dffffc0000000000 RBX: ffffffffc0538140 RCX: 0000000000000007 RDX: 1ffffffff80a702b RSI: 0000000000000001 RDI: ffffffffc0538158 RBP: ffff8881299a6000 R08: 0000000067bbe1e5 R09: 1ffff11023906f20 R10: ffffffffb560ca07 R11: ffffffffb2b43a58 R12: ffff888105bb78
CVE-2025-21999
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2025-21999
Linux
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Linux
Source reference: /containers/cna/affected/1/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "97a32539b9568bb653683349e5a76d02ff3c3e2c",
"lessThan": "eda279586e571b05dff44d48e05f8977ad05855d",
"versionType": "git"
},
{
"status": "affected",
"version": "97a32539b9568bb653683349e5a76d02ff3c3e2c",
"lessThan": "4b0b8445b6fd41e6f62ac90547a0ea9d348de3fa",
"versionType": "git"
},
{
"status": "affected",
"version": "97a32539b9568bb653683349e5a76d02ff3c3e2c",
"lessThan": "966f331403dc3ed04ff64eaf3930cf1267965e53",
"versionType": "git"
},
{
"status": "affected",
"version": "97a32539b9568bb653683349e5a76d02ff3c3e2c",
"lessThan": "63b53198aff2e4e6c5866a4ff73c7891f958ffa4",
"versionType": "git"
},
{
"status": "affected",
"version": "97a32539b9568bb653683349e5a76d02ff3c3e2c",
"lessThan": "ede3e8ac90ae106f0b29cd759aadebc1568f1308",
"versionType": "git"
},
{
"status": "affected",
"version": "97a32539b9568bb653683349e5a76d02ff3c3e2c",
"lessThan": "64dc7c68e040251d9ec6e989acb69f8f6ae4a10b",
"versionType": "git"
},
{
"status": "affected",
"version": "97a32539b9568bb653683349e5a76d02ff3c3e2c",
"lessThan": "654b33ada4ab5e926cd9c570196fefa7bec7c1df",
"versionType": "git"
}
],
"programFiles": [
"fs/proc/generic.c",
"fs/proc/inode.c",
"fs/proc/internal.h",
"include/linux/proc_fs.h"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "5.6"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "5.6",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "5.10.236",
"versionType": "semver",
"lessThanOrEqual": "5.10.*"
},
{
"status": "unaffected",
"version": "5.15.180",
"versionType": "semver",
"lessThanOrEqual": "5.15.*"
},
{
"status": "unaffected",
"version": "6.1.132",
"versionType": "semver",
"lessThanOrEqual": "6.1.*"
},
{
"status": "unaffected",
"version": "6.6.85",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.21",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.13.9",
"versionType": "semver",
"lessThanOrEqual": "6.13.*"
},
{
"status": "unaffected",
"version": "6.14",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"fs/proc/generic.c",
"fs/proc/inode.c",
"fs/proc/internal.h",
"include/linux/proc_fs.h"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2025-21999
Source reference:
/cveMetadata/cveId
Publisher severity
high
Source reference: /containers/cna/metrics
- Event
- #26971 · Revision 1
- Added to Heist Feed
- Publisher date