[PATCH 2/3] tracing: Verify target file before registering a uprobe event

[Steven Rostedt]

From: Jovi Zhang <bookjovi@xxxxxxxxx>

Without this patch, we can register a uprobe event for a directory.
Enabling such a uprobe event would anyway fail.

Example:
$ echo 'p /bin:0x4245c0' > /sys/kernel/debug/tracing/uprobe_events

However dirctories cannot be valid targets for uprobe.
Hence verify if the target is a regular file during the probe
registration.

Signed-off-by: Jovi Zhang <bookjovi@xxxxxxxxx>
Acked-by: Srikar Dronamraju <srikar@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
---
 kernel/trace/trace_uprobe.c |    6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index 4ff9ca4..0bef43c 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -257,6 +257,10 @@ static int create_trace_uprobe(int argc, char **argv)
 		goto fail_address_parse;
 
 	inode = igrab(path.dentry->d_inode);
+	 if (!S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode)) {
+		ret = -EINVAL;
+		goto fail_address_parse;
+	}
 
 	argc -= 2;
 	argv += 2;
@@ -356,7 +360,7 @@ fail_address_parse:
 	if (inode)
 		iput(inode);
 
-	pr_info("Failed to parse address.\n");
+	pr_info("Failed to parse address or file.\n");
 
 	return ret;
 }
-- 
1.7.10.4

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