Since commit
533059281ee5 ("tracing: probeevent: Introduce new
argument fetching code") dropped the $comm support from uprobe
events, this re-enables it.
For $comm support, uses strlcpy() instead of strncpy_from_user()
to copy current task's comm. Because it is in the kernel space,
strncpy_from_user() always fails to copy the comm.
This also uses strlen() instead of strnlen_user() to measure the
length of the comm.
Note that this uses -ECOMM as a token value to fetch the comm
string. If the user-space pointer points -ECOMM, it will be
translated to task->comm.
Link: http://lkml.kernel.org/r/155723734162.9149.4042756162201097965.stgit@devnote2
Fixes:
533059281ee5 ("tracing: probeevent: Introduce new argument fetching code")
Reported-by: Andreas Ziegler <andreas.ziegler@fau.de>
Acked-by: Andreas Ziegler <andreas.ziegler@fau.de>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
/* fetch + deref*N + store + mod + end <= 16, this allows N=12, enough */
#define FETCH_INSN_MAX 16
+#define FETCH_TOKEN_COMM (-ECOMM)
/* Fetch type information table */
struct fetch_type {
if (unlikely(!maxlen))
return -ENOMEM;
- ret = strncpy_from_user(dst, src, maxlen);
+ if (addr == FETCH_TOKEN_COMM)
+ ret = strlcpy(dst, current->comm, maxlen);
+ else
+ ret = strncpy_from_user(dst, src, maxlen);
if (ret >= 0) {
if (ret == maxlen)
dst[ret - 1] = '\0';
int len;
void __user *vaddr = (void __force __user *) addr;
- len = strnlen_user(vaddr, MAX_STRING_SIZE);
+ if (addr == FETCH_TOKEN_COMM)
+ len = strlen(current->comm) + 1;
+ else
+ len = strnlen_user(vaddr, MAX_STRING_SIZE);
return (len > MAX_STRING_SIZE) ? 0 : len;
}
case FETCH_OP_IMM:
val = code->immediate;
break;
+ case FETCH_OP_COMM:
+ val = FETCH_TOKEN_COMM;
+ break;
case FETCH_OP_FOFFS:
val = translate_user_vaddr(code->immediate);
break;