These procfs files contain sensitive information and currently their
mode is 0444. Change this to 0400, so the VFS will be able to block
unprivileged processes from getting file descriptors on arbitrary
privileged /proc/*/{stack,syscall,personality} files.

Cc: Eric W. Biederman <[email protected]>
Acked-by: Kees Cook <[email protected]>
Signed-off-by: Djalal Harouni <[email protected]>
---
 fs/proc/base.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/fs/proc/base.c b/fs/proc/base.c
index 5150706..e69df4b 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -2587,7 +2587,7 @@ static const struct pid_entry tgid_base_stuff[] = {
        REG("environ",    S_IRUSR, proc_environ_operations),
        INF("auxv",       S_IRUSR, proc_pid_auxv),
        ONE("status",     S_IRUGO, proc_pid_status),
-       ONE("personality", S_IRUGO, proc_pid_personality),
+       ONE("personality", S_IRUSR, proc_pid_personality),
        INF("limits",     S_IRUGO, proc_pid_limits),
 #ifdef CONFIG_SCHED_DEBUG
        REG("sched",      S_IRUGO|S_IWUSR, proc_pid_sched_operations),
@@ -2597,7 +2597,7 @@ static const struct pid_entry tgid_base_stuff[] = {
 #endif
        REG("comm",      S_IRUGO|S_IWUSR, proc_pid_set_comm_operations),
 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
-       INF("syscall",    S_IRUGO, proc_pid_syscall),
+       INF("syscall",    S_IRUSR, proc_pid_syscall),
 #endif
        INF("cmdline",    S_IRUGO, proc_pid_cmdline),
        ONE("stat",       S_IRUGO, proc_tgid_stat),
@@ -2625,7 +2625,7 @@ static const struct pid_entry tgid_base_stuff[] = {
        INF("wchan",      S_IRUGO, proc_pid_wchan),
 #endif
 #ifdef CONFIG_STACKTRACE
-       ONE("stack",      S_IRUGO, proc_pid_stack),
+       ONE("stack",      S_IRUSR, proc_pid_stack),
 #endif
 #ifdef CONFIG_SCHEDSTATS
        INF("schedstat",  S_IRUGO, proc_pid_schedstat),
@@ -2926,14 +2926,14 @@ static const struct pid_entry tid_base_stuff[] = {
        REG("environ",   S_IRUSR, proc_environ_operations),
        INF("auxv",      S_IRUSR, proc_pid_auxv),
        ONE("status",    S_IRUGO, proc_pid_status),
-       ONE("personality", S_IRUGO, proc_pid_personality),
+       ONE("personality", S_IRUSR, proc_pid_personality),
        INF("limits",    S_IRUGO, proc_pid_limits),
 #ifdef CONFIG_SCHED_DEBUG
        REG("sched",     S_IRUGO|S_IWUSR, proc_pid_sched_operations),
 #endif
        REG("comm",      S_IRUGO|S_IWUSR, proc_pid_set_comm_operations),
 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
-       INF("syscall",   S_IRUGO, proc_pid_syscall),
+       INF("syscall",   S_IRUSR, proc_pid_syscall),
 #endif
        INF("cmdline",   S_IRUGO, proc_pid_cmdline),
        ONE("stat",      S_IRUGO, proc_tid_stat),
@@ -2963,7 +2963,7 @@ static const struct pid_entry tid_base_stuff[] = {
        INF("wchan",     S_IRUGO, proc_pid_wchan),
 #endif
 #ifdef CONFIG_STACKTRACE
-       ONE("stack",      S_IRUGO, proc_pid_stack),
+       ONE("stack",      S_IRUSR, proc_pid_stack),
 #endif
 #ifdef CONFIG_SCHEDSTATS
        INF("schedstat", S_IRUGO, proc_pid_schedstat),
-- 
1.7.11.7

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