kprobes: Fix to check symbol prefixes correctly

mhiramat · mhiramat · commit 8c8acb8f26cb · 2024-08-05T14:04:03.000+09:00
Since str_has_prefix() takes the prefix as the 2nd argument and the string as the first, is_cfi_preamble_symbol() always fails to check the prefix. Fix the function parameter order so that it correctly check the prefix. Link: https://lore.kernel.org/all/172260679559.362040.7360872132937227206.stgit@devnote2/ Fixes: de02f2a ("kprobes: Prohibit probing on CFI preamble symbol") Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
@@ -1557,8 +1557,8 @@ static bool is_cfi_preamble_symbol(unsigned long addr)
 	if (lookup_symbol_name(addr, symbuf))
 		return false;
 
-	return str_has_prefix("__cfi_", symbuf) ||
-		str_has_prefix("__pfx_", symbuf);
+	return str_has_prefix(symbuf, "__cfi_") ||
+		str_has_prefix(symbuf, "__pfx_");
 }
 
 static int check_kprobe_address_safe(struct kprobe *p,

Original file line number	Diff line number	Diff line change
`@@ -1557,8 +1557,8 @@ static bool is_cfi_preamble_symbol(unsigned long addr)`
`1557`	`1557`	`if (lookup_symbol_name(addr, symbuf))`
`1558`	`1558`	`return false;`
`1559`	`1559`
`1560`		`- return str_has_prefix("__cfi_", symbuf) \|\|`
`1561`		`- str_has_prefix("__pfx_", symbuf);`
	`1560`	`+ return str_has_prefix(symbuf, "__cfi_") \|\|`
	`1561`	`+ str_has_prefix(symbuf, "__pfx_");`
`1562`	`1562`	`}`
`1563`	`1563`
`1564`	`1564`	`static int check_kprobe_address_safe(struct kprobe *p,`