diff options
| author | Mateusz Guzik <mguzik@redhat.com> | 2016-01-20 15:01:05 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-05-26 08:48:55 +0200 |
| commit | a58c00657ec02755fe322eebd11dbf6a24da1d91 (patch) | |
| tree | 613ec0d393b947e187f9237c0c3e5c18441204f8 /mm | |
| parent | 111cb9f5df8a649cd0e57bbacf8d5254a2a8c712 (diff) | |
proc read mm's {arg,env}_{start,end} with mmap semaphore taken.
commit a3b609ef9f8b1dbfe97034ccad6cd3fe71fbe7ab upstream.
Only functions doing more than one read are modified. Consumeres
happened to deal with possibly changing data, but it does not seem like
a good thing to rely on.
Signed-off-by: Mateusz Guzik <mguzik@redhat.com>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Jarod Wilson <jarod@redhat.com>
Cc: Jan Stancek <jstancek@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Anshuman Khandual <anshuman.linux@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/util.c | 16 |
1 files changed, 12 insertions, 4 deletions
diff --git a/mm/util.c b/mm/util.c index 818bbae84721..5fae5b9c2885 100644 --- a/mm/util.c +++ b/mm/util.c @@ -428,17 +428,25 @@ int get_cmdline(struct task_struct *task, char *buffer, int buflen) int res = 0; unsigned int len; struct mm_struct *mm = get_task_mm(task); + unsigned long arg_start, arg_end, env_start, env_end; if (!mm) goto out; if (!mm->arg_end) goto out_mm; /* Shh! No looking before we're done */ - len = mm->arg_end - mm->arg_start; + down_read(&mm->mmap_sem); + arg_start = mm->arg_start; + arg_end = mm->arg_end; + env_start = mm->env_start; + env_end = mm->env_end; + up_read(&mm->mmap_sem); + + len = arg_end - arg_start; if (len > buflen) len = buflen; - res = access_process_vm(task, mm->arg_start, buffer, len, 0); + res = access_process_vm(task, arg_start, buffer, len, 0); /* * If the nul at the end of args has been overwritten, then @@ -449,10 +457,10 @@ int get_cmdline(struct task_struct *task, char *buffer, int buflen) if (len < res) { res = len; } else { - len = mm->env_end - mm->env_start; + len = env_end - env_start; if (len > buflen - res) len = buflen - res; - res += access_process_vm(task, mm->env_start, + res += access_process_vm(task, env_start, buffer+res, len, 0); res = strnlen(buffer, res); } |