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* [PATCH 01/15] modpost: remove incorrect code in do_eisa_entry()
@ 2024-11-19 23:56 Masahiro Yamada
  2024-11-19 23:56 ` [PATCH 02/15] modpost: remove unnecessary check in do_acpi_entry() Masahiro Yamada
                   ` (13 more replies)
  0 siblings, 14 replies; 16+ messages in thread
From: Masahiro Yamada @ 2024-11-19 23:56 UTC (permalink / raw)
  To: linux-kbuild
  Cc: Masahiro Yamada, Andreas Schwab, Jean Delvare, Jochen Friedrich,
	Michal Marek, Nathan Chancellor, Nicolas Schier, Sam Ravnborg,
	linux-kernel

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>
---

 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 c4cc11aa558f..634e40748287 100644
--- a/scripts/mod/file2alias.c
+++ b/scripts/mod/file2alias.c
@@ -809,10 +809,7 @@ 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


^ permalink raw reply related	[flat|nested] 16+ messages in thread

end of thread, other threads:[~2024-11-20  2:38 UTC | newest]

Thread overview: 16+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2024-11-19 23:56 [PATCH 01/15] modpost: remove incorrect code in do_eisa_entry() Masahiro Yamada
2024-11-19 23:56 ` [PATCH 02/15] modpost: remove unnecessary check in do_acpi_entry() Masahiro Yamada
2024-11-19 23:56 ` [PATCH 03/15] modpost: introduce module_alias_printf() helper Masahiro Yamada
2024-11-20  2:37   ` Masahiro Yamada
2024-11-19 23:56 ` [PATCH 04/15] modpost: deduplicate MODULE_ALIAS() for all drivers Masahiro Yamada
2024-11-19 23:56 ` [PATCH 05/15] modpost: remove DEF_FIELD_ADDR_VAR() macro Masahiro Yamada
2024-11-19 23:56 ` [PATCH 06/15] modpost: pass (struct module *) to do_*_entry() functions Masahiro Yamada
2024-11-19 23:56 ` [PATCH 07/15] modpost: call module_alias_printf() from all " Masahiro Yamada
2024-11-19 23:56 ` [PATCH 08/15] modpost: convert do_pnp_card_entries() to a generic handler Masahiro Yamada
2024-11-19 23:56 ` [PATCH 09/15] modpost: convert do_pnp_device_entry() " Masahiro Yamada
2024-11-19 23:56 ` [PATCH 10/15] modpost: convert do_of_table() " Masahiro Yamada
2024-11-19 23:56 ` [PATCH 11/15] modpost: convert do_usb_table() " Masahiro Yamada
2024-11-19 23:56 ` [PATCH 12/15] modpost: move strstarts() to modpost.h Masahiro Yamada
2024-11-19 23:56 ` [PATCH 13/15] modpost: rename variables in handle_moddevtable() Masahiro Yamada
2024-11-19 23:56 ` [PATCH 14/15] modpost: rename alias symbol for MODULE_DEVICE_TABLE() Masahiro Yamada
2024-11-19 23:56 ` [PATCH 15/15] modpost: improve error messages in device_id_check() Masahiro Yamada

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