5.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Masahiro Yamada <masahiroy@xxxxxxxxxx>
[ Upstream commit 0c3e091319e4748cb36ac9a50848903dc6f54054 ]
This function contains multiple bugs after the following commits:
- ac551828993e ("modpost: i2c aliases need no trailing wildcard")
- 6543becf26ff ("mod/file2alias: make modalias generation safe for cross compiling")
Commit ac551828993e inserted the following code to do_eisa_entry():
else
strcat(alias, "*");
This is incorrect because 'alias' is uninitialized. If it is not
NULL-terminated, strcat() could cause a buffer overrun.
Even if 'alias' happens to be zero-filled, it would output:
MODULE_ALIAS("*");
This would match anything. As a result, the module could be loaded by
any unrelated uevent from an unrelated subsystem.
Commit ac551828993e introduced another bug.
Prior to that commit, the conditional check was:
if (eisa->sig[0])
This checked if the first character of eisa_device_id::sig was not '\0'.
However, commit ac551828993e changed it as follows:
if (sig[0])
sig[0] is NOT the first character of the eisa_device_id::sig. The
type of 'sig' is 'char (*)[8]', meaning that the type of 'sig[0]' is
'char [8]' instead of 'char'. 'sig[0]' and 'symval' refer to the same
address, which never becomes NULL.
The correct conversion would have been:
if ((*sig)[0])
However, this if-conditional was meaningless because the earlier change
in commit ac551828993e was incorrect.
This commit removes the entire incorrect code, which should never have
been executed.
Fixes: ac551828993e ("modpost: i2c aliases need no trailing wildcard")
Fixes: 6543becf26ff ("mod/file2alias: make modalias generation safe for cross compiling")
Signed-off-by: Masahiro Yamada <masahiroy@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
scripts/mod/file2alias.c | 5 +----
1 file changed, 1 insertion(+), 4 deletions(-)
diff --git a/scripts/mod/file2alias.c b/scripts/mod/file2alias.c
index 7b845483717b6..f973010943a05 100644
--- a/scripts/mod/file2alias.c
+++ b/scripts/mod/file2alias.c
@@ -786,10 +786,7 @@ static int do_eisa_entry(const char *filename, void *symval,
char *alias)
{
DEF_FIELD_ADDR(symval, eisa_device_id, sig);
- if (sig[0])
- sprintf(alias, EISA_DEVICE_MODALIAS_FMT "*", *sig);
- else
- strcat(alias, "*");
+ sprintf(alias, EISA_DEVICE_MODALIAS_FMT "*", *sig);
return 1;
}
--
2.43.0
