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Message-Id: <346dd92ea62d8469416e12ab71b67b775eb2494b.1674660533.git.legion@kernel.org>
Date: Wed, 25 Jan 2023 16:28:50 +0100
From: Alexey Gladkov <legion@...nel.org>
To: LKML <linux-kernel@...r.kernel.org>, containers@...ts.linux.dev,
linux-fsdevel@...r.kernel.org
Cc: Alexey Dobriyan <adobriyan@...il.com>,
Al Viro <viro@...iv.linux.org.uk>,
Andrew Morton <akpm@...ux-foundation.org>,
Christian Brauner <brauner@...nel.org>,
Val Cowan <vcowan@...hat.com>
Subject: [RFC PATCH v1 3/6] proc: Check that subset= option has been set
Refactor subset option. Before this option had only one value - pid. Now
another meaning has appeared and therefore their combinations are
possible.
Signed-off-by: Alexey Gladkov <legion@...nel.org>
---
fs/proc/generic.c | 4 ++--
fs/proc/inode.c | 16 +++++++++++++---
fs/proc/internal.h | 6 ------
fs/proc/proc_allowlist.c | 22 ++++------------------
fs/proc/root.c | 27 +++++++++++++++++++--------
include/linux/proc_fs.h | 15 +++++----------
6 files changed, 43 insertions(+), 47 deletions(-)
diff --git a/fs/proc/generic.c b/fs/proc/generic.c
index d4c8589987e7..71a38b275814 100644
--- a/fs/proc/generic.c
+++ b/fs/proc/generic.c
@@ -269,7 +269,7 @@ struct dentry *proc_lookup(struct inode *dir, struct dentry *dentry,
{
struct proc_fs_info *fs_info = proc_sb_info(dir->i_sb);
- if (fs_info->pidonly == PROC_PIDONLY_ON && !proc_has_allowlist(fs_info))
+ if ((fs_info->subset & PROC_SUBSET_PIDONLY) && !(fs_info->subset & PROC_SUBSET_ALLOWLIST))
return ERR_PTR(-ENOENT);
return proc_lookup_de(dir, dentry, PDE(dir));
@@ -334,7 +334,7 @@ int proc_readdir(struct file *file, struct dir_context *ctx)
struct inode *inode = file_inode(file);
struct proc_fs_info *fs_info = proc_sb_info(inode->i_sb);
- if (fs_info->pidonly == PROC_PIDONLY_ON && !proc_has_allowlist(fs_info))
+ if ((fs_info->subset & PROC_SUBSET_PIDONLY) && !(fs_info->subset & PROC_SUBSET_ALLOWLIST))
return 1;
return proc_readdir_de(file, ctx, PDE(inode));
diff --git a/fs/proc/inode.c b/fs/proc/inode.c
index f495fdb39151..4c486237a16b 100644
--- a/fs/proc/inode.c
+++ b/fs/proc/inode.c
@@ -184,9 +184,19 @@ static int proc_show_options(struct seq_file *seq, struct dentry *root)
seq_printf(seq, ",gid=%u", from_kgid_munged(&init_user_ns, fs_info->pid_gid));
if (fs_info->hide_pid != HIDEPID_OFF)
seq_printf(seq, ",hidepid=%s", hidepid2str(fs_info->hide_pid));
- if (fs_info->pidonly != PROC_PIDONLY_OFF)
- seq_printf(seq, ",subset=pid");
-
+ if (fs_info->subset & PROC_SUBSET_SET) {
+ bool need_delim = false;
+ seq_printf(seq, ",subset=");
+ if (fs_info->subset & PROC_SUBSET_PIDONLY) {
+ seq_printf(seq, "pid");
+ need_delim = true;
+ }
+ if (fs_info->subset & PROC_SUBSET_ALLOWLIST) {
+ if (need_delim)
+ seq_printf(seq, "+");
+ seq_printf(seq, "allowlist");
+ }
+ }
return 0;
}
diff --git a/fs/proc/internal.h b/fs/proc/internal.h
index 999d105f6f96..3e1b1f29b13d 100644
--- a/fs/proc/internal.h
+++ b/fs/proc/internal.h
@@ -334,14 +334,8 @@ static inline void pde_force_lookup(struct proc_dir_entry *pde)
* proc_allowlist.c
*/
#ifdef CONFIG_PROC_ALLOW_LIST
-extern bool proc_has_allowlist(struct proc_fs_info *);
extern bool proc_pde_access_allowed(struct proc_fs_info *, struct proc_dir_entry *);
#else
-static inline bool proc_has_allowlist(struct proc_fs_info *fs_info)
-{
- return false;
-}
-
static inline bool proc_pde_access_allowed(struct proc_fs_info *fs_info, struct proc_dir_entry *pde)
{
return true;
diff --git a/fs/proc/proc_allowlist.c b/fs/proc/proc_allowlist.c
index b38e11b04199..2153acb8e467 100644
--- a/fs/proc/proc_allowlist.c
+++ b/fs/proc/proc_allowlist.c
@@ -16,38 +16,24 @@
#define FILE_SEQFILE(f) ((struct seq_file *)((f)->private_data))
#define FILE_DATA(f) (FILE_SEQFILE(f)->private)
-bool proc_has_allowlist(struct proc_fs_info *fs_info)
-{
- bool ret;
- unsigned long flags;
-
- read_lock_irqsave(&fs_info->allowlist_lock, flags);
- ret = (fs_info->allowlist == NULL);
- read_unlock_irqrestore(&fs_info->allowlist_lock, flags);
-
- return ret;
-}
-
bool proc_pde_access_allowed(struct proc_fs_info *fs_info, struct proc_dir_entry *de)
{
bool ret = false;
char *ptr;
unsigned long flags;
- read_lock_irqsave(&fs_info->allowlist_lock, flags);
-
- if (!fs_info->allowlist) {
- read_unlock_irqrestore(&fs_info->allowlist_lock, flags);
-
+ if (!(fs_info->subset & PROC_SUBSET_ALLOWLIST)) {
if (!pde_is_allowlist(de))
ret = true;
return ret;
}
+ read_lock_irqsave(&fs_info->allowlist_lock, flags);
+
ptr = fs_info->allowlist;
- while (*ptr != '\0') {
+ while (ptr && *ptr != '\0') {
struct proc_dir_entry *pde;
char *sep, *end;
size_t len, pathlen;
diff --git a/fs/proc/root.c b/fs/proc/root.c
index 1564f5cd118d..6e9b125072e5 100644
--- a/fs/proc/root.c
+++ b/fs/proc/root.c
@@ -31,8 +31,7 @@ struct proc_fs_context {
unsigned int mask;
enum proc_hidepid hidepid;
int gid;
- enum proc_pidonly pidonly;
- enum proc_allowlist allowlist;
+ unsigned int subset;
};
enum proc_param {
@@ -91,6 +90,8 @@ static int proc_parse_subset_param(struct fs_context *fc, char *value)
{
struct proc_fs_context *ctx = fc->fs_private;
+ ctx->subset |= PROC_SUBSET_SET;
+
while (value) {
char *ptr = strchr(value, '+');
@@ -99,10 +100,10 @@ static int proc_parse_subset_param(struct fs_context *fc, char *value)
if (*value != '\0') {
if (!strcmp(value, "pid")) {
- ctx->pidonly = PROC_PIDONLY_ON;
+ ctx->subset |= PROC_SUBSET_PIDONLY;
} else if (IS_ENABLED(CONFIG_PROC_ALLOW_LIST) &&
!strcmp(value, "allowlist")) {
- ctx->allowlist = PROC_ALLOWLIST_ON;
+ ctx->subset |= PROC_SUBSET_ALLOWLIST;
} else {
return invalf(fc, "proc: unsupported subset option - %s\n", value);
}
@@ -169,8 +170,8 @@ static void proc_apply_options(struct proc_fs_info *fs_info,
if (ctx->mask & (1 << Opt_hidepid))
fs_info->hide_pid = ctx->hidepid;
if (ctx->mask & (1 << Opt_subset)) {
- fs_info->pidonly = ctx->pidonly;
- if (ctx->allowlist == PROC_ALLOWLIST_ON) {
+ fs_info->subset = ctx->subset;
+ if (ctx->subset & PROC_SUBSET_ALLOWLIST) {
fs_info->allowlist = proc_init_allowlist();
} else {
fs_info->allowlist = NULL;
@@ -346,14 +347,21 @@ static int proc_root_getattr(struct user_namespace *mnt_userns,
static struct dentry *proc_root_lookup(struct inode * dir, struct dentry * dentry, unsigned int flags)
{
- if (!proc_pid_lookup(dentry, flags))
- return NULL;
+ struct proc_fs_info *fs_info = proc_sb_info(dir->i_sb);
+
+ if (!(fs_info->subset & PROC_SUBSET_SET) || (fs_info->subset & PROC_SUBSET_PIDONLY)) {
+ if (!proc_pid_lookup(dentry, flags))
+ return NULL;
+ }
return proc_lookup(dir, dentry, flags);
}
static int proc_root_readdir(struct file *file, struct dir_context *ctx)
{
+ struct inode *inode = file_inode(file);
+ struct proc_fs_info *fs_info = proc_sb_info(inode->i_sb);
+
if (ctx->pos < FIRST_PROCESS_ENTRY) {
int error = proc_readdir(file, ctx);
if (unlikely(error <= 0))
@@ -361,6 +369,9 @@ static int proc_root_readdir(struct file *file, struct dir_context *ctx)
ctx->pos = FIRST_PROCESS_ENTRY;
}
+ if ((fs_info->subset & PROC_SUBSET_SET) && !(fs_info->subset & PROC_SUBSET_PIDONLY))
+ return 1;
+
return proc_pid_readdir(file, ctx);
}
diff --git a/include/linux/proc_fs.h b/include/linux/proc_fs.h
index 9105d75aeb18..08d0d0ae6e42 100644
--- a/include/linux/proc_fs.h
+++ b/include/linux/proc_fs.h
@@ -53,15 +53,10 @@ enum proc_hidepid {
HIDEPID_NOT_PTRACEABLE = 4, /* Limit pids to only ptraceable pids */
};
-/* definitions for proc mount option pidonly */
-enum proc_pidonly {
- PROC_PIDONLY_OFF = 0,
- PROC_PIDONLY_ON = 1,
-};
-
-enum proc_allowlist {
- PROC_ALLOWLIST_OFF = 0,
- PROC_ALLOWLIST_ON = 1,
+enum proc_subset {
+ PROC_SUBSET_SET = (1 << 0),
+ PROC_SUBSET_PIDONLY = (1 << 1),
+ PROC_SUBSET_ALLOWLIST = (1 << 2),
};
struct proc_fs_info {
@@ -70,7 +65,7 @@ struct proc_fs_info {
struct dentry *proc_thread_self; /* For /proc/thread-self */
kgid_t pid_gid;
enum proc_hidepid hide_pid;
- enum proc_pidonly pidonly;
+ unsigned int subset;
char *allowlist;
rwlock_t allowlist_lock;
};
--
2.33.6
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