From bd24651ec0d403085dcb0efda71c4431664edd4a Mon Sep 17 00:00:00 2001 From: Salvatore Bonaccorso Date: Mon, 25 Aug 2025 22:41:12 +0200 Subject: [PATCH] proc: fix missing pde_set_flags() for net proc files Apply patch for a regression in 6.16.1. This has not yet been applied upstream but has been tested and looks OK to me. (cherry picked from commit 8765ecb3395367b241c99adb4b881bdd7cf32e7c) [Salvatore Bonaccorso: Do not explicitly mention regression from 6.16.1] (cherry picked from commit 62a4ef2d64695477c8c7d1798c940a64b85a47d1) --- debian/changelog | 1 + ...ing-pde_set_flags-for-net-proc-files.patch | 108 ++++++++++++++++++ debian/patches/series | 1 + 3 files changed, 110 insertions(+) create mode 100644 debian/patches/bugfix/all/proc-fix-missing-pde_set_flags-for-net-proc-files.patch diff --git a/debian/changelog b/debian/changelog index 2784f742e7..fa4eb1b206 100644 --- a/debian/changelog +++ b/debian/changelog @@ -252,6 +252,7 @@ linux (6.1.148-1) UNRELEASED; urgency=medium * Delete ABI name suffix and ABI reference * d/salsa-ci.yml: Ignore pycodestyle error E241 * d/rules.real: Move module installation to the image build rule + * proc: fix missing pde_set_flags() for net proc files [ Salvatore Bonaccorso ] * [amd64] udeb: kernel-image: Include SPI drivers diff --git a/debian/patches/bugfix/all/proc-fix-missing-pde_set_flags-for-net-proc-files.patch b/debian/patches/bugfix/all/proc-fix-missing-pde_set_flags-for-net-proc-files.patch new file mode 100644 index 0000000000..0be9a9a2de --- /dev/null +++ b/debian/patches/bugfix/all/proc-fix-missing-pde_set_flags-for-net-proc-files.patch @@ -0,0 +1,108 @@ +From: wangzijie +Subject: proc: fix missing pde_set_flags() for net proc files +Date: Thu, 21 Aug 2025 18:58:06 +0800 +Origin: https://lore.kernel.org/stable/20250821105806.1453833-1-wangzijie1@honor.com/ + +To avoid potential UAF issues during module removal races, we use pde_set_flags() +to save proc_ops flags in PDE itself before proc_register(), and then use +pde_has_proc_*() helpers instead of directly dereferencing pde->proc_ops->*. + +However, the pde_set_flags() call was missing when creating net related proc files. +This omission caused incorrect behavior which FMODE_LSEEK was being cleared +inappropriately in proc_reg_open() for net proc files. Lars reported it in this link[1]. + +Fix this by ensuring pde_set_flags() is called when register proc entry, and add +NULL check for proc_ops in pde_set_flags(). + +[1]: https://lore.kernel.org/all/20250815195616.64497967@chagall.paradoxon.rec/ + +Fixes: ff7ec8dc1b64 ("proc: use the same treatment to check proc_lseek as ones for proc_read_iter et.al") +Cc: stable@vger.kernel.org +Reported-by: Lars Wendler +Signed-off-by: wangzijie +--- + fs/proc/generic.c | 38 +++++++++++++++++++++----------------- + 1 file changed, 21 insertions(+), 17 deletions(-) + +--- a/fs/proc/generic.c ++++ b/fs/proc/generic.c +@@ -364,6 +364,25 @@ static const struct inode_operations pro + .setattr = proc_notify_change, + }; + ++static void pde_set_flags(struct proc_dir_entry *pde) ++{ ++ const struct proc_ops *proc_ops = pde->proc_ops; ++ ++ if (!proc_ops) ++ return; ++ ++ if (proc_ops->proc_flags & PROC_ENTRY_PERMANENT) ++ pde->flags |= PROC_ENTRY_PERMANENT; ++ if (proc_ops->proc_read_iter) ++ pde->flags |= PROC_ENTRY_proc_read_iter; ++#ifdef CONFIG_COMPAT ++ if (proc_ops->proc_compat_ioctl) ++ pde->flags |= PROC_ENTRY_proc_compat_ioctl; ++#endif ++ if (proc_ops->proc_lseek) ++ pde->flags |= PROC_ENTRY_proc_lseek; ++} ++ + /* returns the registered entry, or frees dp and returns NULL on failure */ + struct proc_dir_entry *proc_register(struct proc_dir_entry *dir, + struct proc_dir_entry *dp) +@@ -371,6 +390,8 @@ struct proc_dir_entry *proc_register(str + if (proc_alloc_inum(&dp->low_ino)) + goto out_free_entry; + ++ pde_set_flags(dp); ++ + write_lock(&proc_subdir_lock); + dp->parent = dir; + if (pde_subdir_insert(dir, dp) == false) { +@@ -559,20 +580,6 @@ struct proc_dir_entry *proc_create_reg(c + return p; + } + +-static void pde_set_flags(struct proc_dir_entry *pde) +-{ +- if (pde->proc_ops->proc_flags & PROC_ENTRY_PERMANENT) +- pde->flags |= PROC_ENTRY_PERMANENT; +- if (pde->proc_ops->proc_read_iter) +- pde->flags |= PROC_ENTRY_proc_read_iter; +-#ifdef CONFIG_COMPAT +- 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, + struct proc_dir_entry *parent, + const struct proc_ops *proc_ops, void *data) +@@ -583,7 +590,6 @@ struct proc_dir_entry *proc_create_data( + if (!p) + return NULL; + p->proc_ops = proc_ops; +- pde_set_flags(p); + return proc_register(parent, p); + } + EXPORT_SYMBOL(proc_create_data); +@@ -634,7 +640,6 @@ struct proc_dir_entry *proc_create_seq_p + p->proc_ops = &proc_seq_ops; + p->seq_ops = ops; + p->state_size = state_size; +- pde_set_flags(p); + return proc_register(parent, p); + } + EXPORT_SYMBOL(proc_create_seq_private); +@@ -665,7 +670,6 @@ struct proc_dir_entry *proc_create_singl + return NULL; + p->proc_ops = &proc_single_ops; + p->single_show = show; +- pde_set_flags(p); + return proc_register(parent, p); + } + EXPORT_SYMBOL(proc_create_single_data); diff --git a/debian/patches/series b/debian/patches/series index 93a938f1f5..32051524f4 100644 --- a/debian/patches/series +++ b/debian/patches/series @@ -104,6 +104,7 @@ bugfix/all/disable-some-marvell-phys.patch bugfix/all/fs-add-module_softdep-declarations-for-hard-coded-cr.patch bugfix/all/netlink-avoid-infinite-retry-looping-in-netlink_unic.patch bugfix/all/ext4-don-t-try-to-clear-the-orphan_present-feature-b.patch +bugfix/all/proc-fix-missing-pde_set_flags-for-net-proc-files.patch # Miscellaneous features