aports/community/libvpx/fix-double-free.patch
ptrcnull 5f986abad8 community/libvpx: upgrade to 1.15.1, backport security fix
related to CVE-2025-5263 / MFSA-TMP-2025-0001
2025-05-31 18:52:07 +02:00

59 lines
2.4 KiB
Diff

From 1c758781c428c0e895645b95b8ff1512b6bdcecb Mon Sep 17 00:00:00 2001
From: James Zern <jzern@google.com>
Date: Wed, 30 Apr 2025 19:28:48 -0700
Subject: [PATCH] vpx_codec_enc_init_multi: fix double free on init failure
In `vp8e_init()`, the encoder would take ownership of
`mr_cfg.mr_low_res_mode_info` even if `vp8_create_compressor()` failed.
This caused confusion at the call site as other failures in
`vp8e_init()` did not result in ownership transfer and the caller would
free the memory. In the case of `vp8_create_compressor()` failure both
the caller and `vpx_codec_destroy()` would free the memory, causing a
crash. `mr_*` related variables are now cleared on failure to prevent
this situation.
Bug: webm:413411335
Bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1962421
Change-Id: Ie951d42b9029a586bf9059b650bd8863db9f9ffc
---
vp8/vp8_cx_iface.c | 12 +++++++++++-
vpx/src/vpx_encoder.c | 3 +++
2 files changed, 14 insertions(+), 1 deletion(-)
diff --git a/vp8/vp8_cx_iface.c b/vp8/vp8_cx_iface.c
index 38456d2b90c..35c94fb0434 100644
--- a/vp8/vp8_cx_iface.c
+++ b/vp8/vp8_cx_iface.c
@@ -732,7 +732,17 @@ static vpx_codec_err_t vp8e_init(vpx_codec_ctx_t *ctx,
set_vp8e_config(&priv->oxcf, priv->cfg, priv->vp8_cfg, mr_cfg);
priv->cpi = vp8_create_compressor(&priv->oxcf);
- if (!priv->cpi) res = VPX_CODEC_MEM_ERROR;
+ if (!priv->cpi) {
+#if CONFIG_MULTI_RES_ENCODING
+ // Release ownership of mr_cfg->mr_low_res_mode_info on failure. This
+ // prevents ownership confusion with the caller and avoids a double
+ // free when vpx_codec_destroy() is called on this instance.
+ priv->oxcf.mr_total_resolutions = 0;
+ priv->oxcf.mr_encoder_id = 0;
+ priv->oxcf.mr_low_res_mode_info = NULL;
+#endif
+ res = VPX_CODEC_MEM_ERROR;
+ }
}
}
diff --git a/vpx/src/vpx_encoder.c b/vpx/src/vpx_encoder.c
index 001d854abe9..3af4cea3a70 100644
--- a/vpx/src/vpx_encoder.c
+++ b/vpx/src/vpx_encoder.c
@@ -114,6 +114,9 @@ vpx_codec_err_t vpx_codec_enc_init_multi_ver(
ctx->priv = NULL;
ctx->init_flags = flags;
ctx->config.enc = cfg;
+ // ctx takes ownership of mr_cfg.mr_low_res_mode_info if and only if
+ // this call succeeds. The first ctx entry in the array is
+ // responsible for freeing the memory.
res = ctx->iface->init(ctx, &mr_cfg);
}