Messages in this thread Patch in this message | | | From | John Stultz <> | Subject | [PATCH 13/13] android: ram_console: honor dmesg_restrict | Date | Wed, 7 Mar 2012 13:58:23 -0800 |
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From: Nick Kralevich <nnk@google.com>
The Linux kernel has a setting called dmesg_restrict. When true, only processes with CAP_SYSLOG can view the kernel dmesg logs. This helps prevent leaking of kernel information into user space.
On Android, it's possible to bypass these restrictions by viewing /proc/last_kmsg.
This change makes /proc/last_kmsg require the same permissions as dmesg.
Bug: 5555691 CC: Greg KH <gregkh@linuxfoundation.org> CC: Android Kernel Team <kernel-team@android.com> Change-Id: I50ecb74012ef2ac0a3cff7325192634341fddae9 Signed-off-by: Nick Kralevich <nnk@google.com> Signed-off-by: John Stultz <john.stultz@linaro.org> --- drivers/staging/android/ram_console.c | 3 +++ 1 files changed, 3 insertions(+), 0 deletions(-)
diff --git a/drivers/staging/android/ram_console.c b/drivers/staging/android/ram_console.c index d956b84..b242be2 100644 --- a/drivers/staging/android/ram_console.c +++ b/drivers/staging/android/ram_console.c @@ -99,6 +99,9 @@ static ssize_t ram_console_read_old(struct file *file, char __user *buf, char *str; int ret; + if (dmesg_restrict && !capable(CAP_SYSLOG)) + return -EPERM; + /* Main last_kmsg log */ if (pos < old_log_size) { count = min(len, (size_t)(old_log_size - pos)); -- 1.7.3.2.146.gca209
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