From 3482062c786ce4233f8ed3224d824184f53ec154 Mon Sep 17 00:00:00 2001 From: Richard Fitzgerald Date: Mon, 14 Sep 2026 13:26:11 +0100 Subject: [PATCH] ASoC: cs-amp-lib: Prevent NULL pointer if efi variable is zero length In cs_amp_alloc_get_efi_variable() the first call to cs_amp_get_efi_variable() might return EFI_SUCCESS if the variable exists with zero length. Trap this and return -ENOENT to prevent returning an unexpected NULL pointer. The first cs_amp_get_efi_variable() call was assumed to return EFI_BUFFER_TOO_SMALL if the variable existed, but if instead it returned EFI_SUCCESS this would be converted to 0 by cs_amp_convert_efi_status() and then be returned as a NULL pointer. Fixes: 00fd40bc7acec ("ASoC: cs-amp-lib: Support Dell SSIDExV2 UEFI variable") Signed-off-by: Richard Fitzgerald Link: https://patch.msgid.link/20260914122611.2783563-1-rf@opensource.cirrus.com Signed-off-by: Mark Brown --- sound/soc/codecs/cs-amp-lib.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/sound/soc/codecs/cs-amp-lib.c b/sound/soc/codecs/cs-amp-lib.c index 41a9a5b005c6..9bc19d2e1639 100644 --- a/sound/soc/codecs/cs-amp-lib.c +++ b/sound/soc/codecs/cs-amp-lib.c @@ -317,6 +317,8 @@ static void *cs_amp_alloc_get_efi_variable(efi_char16_t *name, unsigned long size = 0; status = cs_amp_get_efi_variable(name, guid, NULL, &size, NULL); + if (status == EFI_SUCCESS) + return ERR_PTR(-ENOENT); if (status != EFI_BUFFER_TOO_SMALL) return ERR_PTR(cs_amp_convert_efi_status(status));