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| author | Alexey Dobriyan <adobriyan@gmail.com> | 2015-07-18 01:24:09 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2015-07-18 01:39:54 +0200 |
| commit | 3581d458c39bc5e58ceeeaf51796625bc978d2eb (patch) | |
| tree | 4a996d189d715782dc31a2c7ad7e12de32b7de77 /fs/proc | |
| parent | dma-debug: skip debug_dma_assert_idle() when disabled (diff) | |
| download | linux-3581d458c39bc5e58ceeeaf51796625bc978d2eb.tar.xz linux-3581d458c39bc5e58ceeeaf51796625bc978d2eb.zip | |
/proc/$PID/cmdline: fixup empty ARGV case
/proc/*/cmdline code checks if it should look at ENVP area by checking
last byte of ARGV area:
rv = access_remote_vm(mm, arg_end - 1, &c, 1, 0);
if (rv <= 0)
goto out_free_page;
If ARGV is somehow made empty (by doing execve(..., NULL, ...) or
manually setting ->arg_start and ->arg_end to equal values), the decision
will be based on byte which doesn't even belong to ARGV/ENVP.
So, quickly check if ARGV area is empty and report 0 to match previous
behaviour.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/proc')
| -rw-r--r-- | fs/proc/base.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/fs/proc/base.c b/fs/proc/base.c index 87782e874b6a..aa50d1ac28fc 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -243,6 +243,11 @@ static ssize_t proc_pid_cmdline_read(struct file *file, char __user *buf, len1 = arg_end - arg_start; len2 = env_end - env_start; + /* Empty ARGV. */ + if (len1 == 0) { + rv = 0; + goto out_free_page; + } /* * Inherently racy -- command line shares address space * with code and data. |