diff options
| author | Linus Torvalds <torvalds@linux-foundation.org> | 2011-12-20 11:41:17 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2011-12-20 11:41:17 -0800 |
| commit | a205b082189bf914959a667a5c83ea145bba3fb5 (patch) | |
| tree | 8e4a05c7eebe9039136d2880e64dc782b73a1c1a /drivers | |
| parent | 455ba0c0b7e1d2c72a45808115ef35512e3ae7b0 (diff) | |
| parent | 913050b91eb94f194392dd797b1ff3779f606ac0 (diff) | |
Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
oprofile: Fix uninitialized memory access when writing to writing to oprofilefs
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/oprofile/oprofile_files.c | 7 | ||||
| -rw-r--r-- | drivers/oprofile/oprofilefs.c | 11 |
2 files changed, 13 insertions, 5 deletions
diff --git a/drivers/oprofile/oprofile_files.c b/drivers/oprofile/oprofile_files.c index 89f63456646f..84a208dbed93 100644 --- a/drivers/oprofile/oprofile_files.c +++ b/drivers/oprofile/oprofile_files.c @@ -45,7 +45,7 @@ static ssize_t timeout_write(struct file *file, char const __user *buf, return -EINVAL; retval = oprofilefs_ulong_from_user(&val, buf, count); - if (retval) + if (retval <= 0) return retval; retval = oprofile_set_timeout(val); @@ -84,7 +84,7 @@ static ssize_t depth_write(struct file *file, char const __user *buf, size_t cou return -EINVAL; retval = oprofilefs_ulong_from_user(&val, buf, count); - if (retval) + if (retval <= 0) return retval; retval = oprofile_set_ulong(&oprofile_backtrace_depth, val); @@ -141,9 +141,10 @@ static ssize_t enable_write(struct file *file, char const __user *buf, size_t co return -EINVAL; retval = oprofilefs_ulong_from_user(&val, buf, count); - if (retval) + if (retval <= 0) return retval; + retval = 0; if (val) retval = oprofile_start(); else diff --git a/drivers/oprofile/oprofilefs.c b/drivers/oprofile/oprofilefs.c index d0de6cc2d7a5..2f0aa0f700e6 100644 --- a/drivers/oprofile/oprofilefs.c +++ b/drivers/oprofile/oprofilefs.c @@ -60,6 +60,13 @@ ssize_t oprofilefs_ulong_to_user(unsigned long val, char __user *buf, size_t cou } +/* + * Note: If oprofilefs_ulong_from_user() returns 0, then *val remains + * unchanged and might be uninitialized. This follows write syscall + * implementation when count is zero: "If count is zero ... [and if] + * no errors are detected, 0 will be returned without causing any + * other effect." (man 2 write) + */ int oprofilefs_ulong_from_user(unsigned long *val, char const __user *buf, size_t count) { char tmpbuf[TMPBUFSIZE]; @@ -79,7 +86,7 @@ int oprofilefs_ulong_from_user(unsigned long *val, char const __user *buf, size_ raw_spin_lock_irqsave(&oprofilefs_lock, flags); *val = simple_strtoul(tmpbuf, NULL, 0); raw_spin_unlock_irqrestore(&oprofilefs_lock, flags); - return 0; + return count; } @@ -99,7 +106,7 @@ static ssize_t ulong_write_file(struct file *file, char const __user *buf, size_ return -EINVAL; retval = oprofilefs_ulong_from_user(&value, buf, count); - if (retval) + if (retval <= 0) return retval; retval = oprofile_set_ulong(file->private_data, value); |