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authorQingyu Zhang <usupergate@gmail.com>2026-09-02 15:39:18 +0800
committerTakashi Iwai <tiwai@suse.de>2026-09-02 11:10:49 +0200
commitadeee7187694719890aaffdc14b7e89cfd736f1d (patch)
tree776c1e24e4049e2a410a09d1e367bff802919ccb
parent82cfab6a52621febf36752bd5ed5184f82c96e07 (diff)
ALSA: ump: do not touch legacy_rmidi before it exists
snd_ump_parse_endpoint() sets ump->parsed on every exit, including error, before the caller attaches the legacy rawmidi device. ump_handle_ep_name_msg() then treats parsed as "legacy_rmidi is live" and calls ump_legacy_set_rawmidi_name(), which snprintf()s into ump->legacy_rmidi->name. If a UMP packet arrives in that window (IRQ path from snd_ump_receive), legacy_rmidi is still NULL (KASAN null-ptr-deref in snprintf). Guard the legacy helpers. parsed only means endpoint info was parsed, not that legacy_rmidi exists. Fixes: 37e0e14128e0 ("ALSA: ump: Support UMP Endpoint and Function Block parsing") Signed-off-by: Qingyu Zhang <usupergate@gmail.com> Link: https://patch.msgid.link/20260902073918.880245-1-usupergate@gmail.com Signed-off-by: Takashi Iwai <tiwai@suse.de>
-rw-r--r--sound/core/ump.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/sound/core/ump.c b/sound/core/ump.c
index d183c8a000bd..3d1a2ed3b476 100644
--- a/sound/core/ump.c
+++ b/sound/core/ump.c
@@ -1335,6 +1335,8 @@ static void update_legacy_names(struct snd_ump_endpoint *ump)
{
struct snd_rawmidi *rmidi = ump->legacy_rmidi;
+ if (!rmidi)
+ return;
update_legacy_substreams(ump, rmidi, SNDRV_RAWMIDI_STREAM_INPUT);
update_legacy_substreams(ump, rmidi, SNDRV_RAWMIDI_STREAM_OUTPUT);
}
@@ -1343,6 +1345,8 @@ static void ump_legacy_set_rawmidi_name(struct snd_ump_endpoint *ump)
{
struct snd_rawmidi *rmidi = ump->legacy_rmidi;
+ if (!rmidi)
+ return;
snprintf(rmidi->name, sizeof(rmidi->name), "%.68s (MIDI 1.0)",
ump->core.name);
}