4.19-stable review patch. If anyone has any objections, please let me know.
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From: Masahiro Yamada masahiroy@kernel.org
[ 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@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- 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 90868df7865e3..adcaabf408949 100644 --- a/scripts/mod/file2alias.c +++ b/scripts/mod/file2alias.c @@ -763,10 +763,7 @@ 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; }