[ Upstream commit 0c3e091319e4748cb36ac9a50848903dc6f54054 ]
This function contains multiple bugs after the following commits:
- ac55182899 ("modpost: i2c aliases need no trailing wildcard")
- 6543becf26 ("mod/file2alias: make modalias generation safe for cross compiling")
Commit ac55182899 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 ac55182899 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 ac55182899 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: ac55182899 ("modpost: i2c aliases need no trailing wildcard")
Fixes: 6543becf26 ("mod/file2alias: make modalias generation safe for cross compiling")
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
e70c21daad