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author | Steven Rostedt (Google) <rostedt@goodmis.org> | 2022-03-08 16:39:45 +0100 |
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committer | Steven Rostedt (Google) <rostedt@goodmis.org> | 2022-03-10 23:41:18 +0100 |
commit | 5677a3d713ad795e3ce32d631941e982777b43db (patch) | |
tree | 3721f7325edb65ffe1d2484da43a39a3e9574b04 /net/switchdev/switchdev.c | |
parent | user_events: Fix potential uninitialized pointer while parsing field (diff) | |
download | linux-5677a3d713ad795e3ce32d631941e982777b43db.tar.xz linux-5677a3d713ad795e3ce32d631941e982777b43db.zip |
tracing: Fix last_cmd_set() string management in histogram code
Using strnlen(dest, str, n) is confusing, as the size of dest must be
strlen(dest) + n + 1. Even more confusing, using sizeof(string constant)
gives you strlen(string constant) + 1 and not just strlen().
These two together made using strncat() with a constant string a bit off
in the calculations as we have:
len = sizeof(HIST_PREFIX) + strlen(str) + 1;
kfree(last_cmd);
last_cmd = kzalloc(len, GFP_KERNEL);
strcpy(last_cmd, HIST_PREFIX);
len -= sizeof(HIST_PREFIX) + 1;
strncat(last_cmd, str, len);
The above works if we s/sizeof/strlen/ with HIST_PREFIX (which is defined
as "hist:", but because sizeof(HIST_PREFIX) is equal to
strlen(HIST_PREFIX) + 1, we can drop the +1 in the code. But at least
comment that we are doing so.
Link: https://lore.kernel.org/all/202203082112.Iu7tvFl4-lkp@intel.com/
Fixes: 9f8e5aee93ed2 ("tracing: Fix allocation of last_cmd in last_cmd_set()")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Diffstat (limited to 'net/switchdev/switchdev.c')
0 files changed, 0 insertions, 0 deletions