diff options
| author | Sebastian Schmidt | 2014-10-19 20:05:15 +0200 |
|---|---|---|
| committer | Tony Luck | 2014-11-05 09:59:48 -0800 |
| commit | 68c4a4f8abc60c9440ede9cd123d48b78325f7a3 (patch) | |
| tree | ef8aefb7d8c3769204116ff65cfa48551464a275 | |
| parent | a28726b4fb624f81d637a8afb9ea12fc16500f61 (diff) | |
pstore: Honor dmesg_restrict sysctl on dmesg dumps
When the kernel.dmesg_restrict restriction is in place, only users with
CAP_SYSLOG should be able to access crash dumps (like: attacker is
trying to exploit a bug, watchdog reboots, attacker can happily read
crash dumps and logs).
This puts the restriction on console-* types as well as sensitive
information could have been leaked there.
Other log types are unaffected.
Signed-off-by: Sebastian Schmidt <yath@yath.de>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Tony Luck <tony.luck@intel.com>
| -rw-r--r-- | fs/pstore/inode.c | 22 | ||||
| -rw-r--r-- | include/linux/syslog.h | 1 | ||||
| -rw-r--r-- | kernel/printk/printk.c | 2 |
3 files changed, 24 insertions, 1 deletions
diff --git a/fs/pstore/inode.c b/fs/pstore/inode.c index fafb7a02a5d6..50416602774d 100644 --- a/fs/pstore/inode.c +++ b/fs/pstore/inode.c @@ -36,6 +36,7 @@ #include <linux/slab.h> #include <linux/spinlock.h> #include <linux/uaccess.h> +#include <linux/syslog.h> #include "internal.h" @@ -120,6 +121,18 @@ static const struct seq_operations pstore_ftrace_seq_ops = { .show = pstore_ftrace_seq_show, }; +static int pstore_check_syslog_permissions(struct pstore_private *ps) +{ + switch (ps->type) { + case PSTORE_TYPE_DMESG: + case PSTORE_TYPE_CONSOLE: + return check_syslog_permissions(SYSLOG_ACTION_READ_ALL, + SYSLOG_FROM_READER); + default: + return 0; + } +} + static ssize_t pstore_file_read(struct file *file, char __user *userbuf, size_t count, loff_t *ppos) { @@ -138,6 +151,10 @@ static int pstore_file_open(struct inode *inode, struct file *file) int err; const struct seq_operations *sops = NULL; + err = pstore_check_syslog_permissions(ps); + if (err) + return err; + if (ps->type == PSTORE_TYPE_FTRACE) sops = &pstore_ftrace_seq_ops; @@ -174,6 +191,11 @@ static const struct file_operations pstore_file_operations = { static int pstore_unlink(struct inode *dir, struct dentry *dentry) { struct pstore_private *p = dentry->d_inode->i_private; + int err; + + err = pstore_check_syslog_permissions(p); + if (err) + return err; if (p->psi->erase) p->psi->erase(p->type, p->id, p->count, diff --git a/include/linux/syslog.h b/include/linux/syslog.h index 98a3153c0f96..9def5297dbb7 100644 --- a/include/linux/syslog.h +++ b/include/linux/syslog.h @@ -48,5 +48,6 @@ #define SYSLOG_FROM_PROC 1 int do_syslog(int type, char __user *buf, int count, bool from_file); +int check_syslog_permissions(int type, bool from_file); #endif /* _LINUX_SYSLOG_H */ diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index ced2b84b1cb7..c8755e7e1dba 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -480,7 +480,7 @@ static int syslog_action_restricted(int type) type != SYSLOG_ACTION_SIZE_BUFFER; } -static int check_syslog_permissions(int type, bool from_file) +int check_syslog_permissions(int type, bool from_file) { /* * If this is from /proc/kmsg and we've already opened it, then we've |