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authorMasami Hiramatsu <mhiramat@kernel.org>2019-05-07 22:55:41 +0900
committerSteven Rostedt (VMware) <rostedt@goodmis.org>2019-05-08 12:15:11 -0400
commit4dd537aca25dd2e0e8aca8b8923930cbe6240003 (patch)
tree4237d1d2cd0c827fd2d3edd8040b5fd6a9337375 /kernel
parent9e298e8604088a600d8100a111a532a9d342af09 (diff)
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tracing: uprobes: Re-enable $comm support for uprobe events
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>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/trace/trace_probe.h1
-rw-r--r--kernel/trace/trace_uprobe.c13
2 files changed, 12 insertions, 2 deletions
diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h
index b7737666c1a8..f9a8c632188b 100644
--- a/kernel/trace/trace_probe.h
+++ b/kernel/trace/trace_probe.h
@@ -124,6 +124,7 @@ struct fetch_insn {
/* 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 {
diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index cd8750a72768..eb7e06b54741 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -156,7 +156,10 @@ fetch_store_string(unsigned long addr, void *dest, void *base)
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';
@@ -180,7 +183,10 @@ fetch_store_strlen(unsigned long addr)
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;
}
@@ -220,6 +226,9 @@ process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest,
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;