6.15-stable review patch. If anyone has any objections, please let me know.
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From: wangzijie wangzijie1@honor.com
[ Upstream commit ff7ec8dc1b646296f8d94c39339e8d3833d16c05 ]
Check pde->proc_ops->proc_lseek directly may cause UAF in rmmod scenario. It's a gap in proc_reg_open() after commit 654b33ada4ab("proc: fix UAF in proc_get_inode()"). Followed by AI Viro's suggestion, fix it in same manner.
Link: https://lkml.kernel.org/r/20250607021353.1127963-1-wangzijie1@honor.com Fixes: 3f61631d47f1 ("take care to handle NULL ->proc_lseek()") Signed-off-by: wangzijie wangzijie1@honor.com Reviewed-by: Alexey Dobriyan adobriyan@gmail.com Cc: Alexei Starovoitov ast@kernel.org Cc: Al Viro viro@zeniv.linux.org.uk Cc: "Edgecombe, Rick P" rick.p.edgecombe@intel.com Cc: Kirill A. Shuemov kirill.shutemov@linux.intel.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- fs/proc/generic.c | 2 ++ fs/proc/inode.c | 2 +- fs/proc/internal.h | 5 +++++ include/linux/proc_fs.h | 1 + 4 files changed, 9 insertions(+), 1 deletion(-)
diff --git a/fs/proc/generic.c b/fs/proc/generic.c index a3e22803cddf..e0e50914ab25 100644 --- a/fs/proc/generic.c +++ b/fs/proc/generic.c @@ -569,6 +569,8 @@ static void pde_set_flags(struct proc_dir_entry *pde) if (pde->proc_ops->proc_compat_ioctl) pde->flags |= PROC_ENTRY_proc_compat_ioctl; #endif + if (pde->proc_ops->proc_lseek) + pde->flags |= PROC_ENTRY_proc_lseek; }
struct proc_dir_entry *proc_create_data(const char *name, umode_t mode, diff --git a/fs/proc/inode.c b/fs/proc/inode.c index 3604b616311c..129490151be1 100644 --- a/fs/proc/inode.c +++ b/fs/proc/inode.c @@ -473,7 +473,7 @@ static int proc_reg_open(struct inode *inode, struct file *file) typeof_member(struct proc_ops, proc_open) open; struct pde_opener *pdeo;
- if (!pde->proc_ops->proc_lseek) + if (!pde_has_proc_lseek(pde)) file->f_mode &= ~FMODE_LSEEK;
if (pde_is_permanent(pde)) { diff --git a/fs/proc/internal.h b/fs/proc/internal.h index 96122e91c645..3d48ffe72583 100644 --- a/fs/proc/internal.h +++ b/fs/proc/internal.h @@ -99,6 +99,11 @@ static inline bool pde_has_proc_compat_ioctl(const struct proc_dir_entry *pde) #endif }
+static inline bool pde_has_proc_lseek(const struct proc_dir_entry *pde) +{ + return pde->flags & PROC_ENTRY_proc_lseek; +} + extern struct kmem_cache *proc_dir_entry_cache; void pde_free(struct proc_dir_entry *pde);
diff --git a/include/linux/proc_fs.h b/include/linux/proc_fs.h index ea62201c74c4..703d0c76cc9a 100644 --- a/include/linux/proc_fs.h +++ b/include/linux/proc_fs.h @@ -27,6 +27,7 @@ enum {
PROC_ENTRY_proc_read_iter = 1U << 1, PROC_ENTRY_proc_compat_ioctl = 1U << 2, + PROC_ENTRY_proc_lseek = 1U << 3, };
struct proc_ops {