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out_azure_blob: fixed double free #10235

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Merged
edsiper merged 1 commit into from
Apr 22, 2025
Merged

out_azure_blob: fixed double free #10235

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22 changes: 16 additions & 6 deletions plugins/out_azure_blob/azure_blob.c
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Original file line number Diff line number Diff line change
Expand Up @@ -388,8 +388,12 @@ static int send_blob(struct flb_config *config,
}

if (!uri) {
flb_free(block_id);
if (block_id != NULL) {
flb_free(block_id);
}

flb_sds_destroy(ref_name);

return FLB_RETRY;
}

Expand All @@ -403,7 +407,11 @@ static int send_blob(struct flb_config *config,
&payload_buf, &payload_size);
if (ret != 0) {
flb_sds_destroy(uri);
flb_free(block_id);

if (block_id != NULL) {
flb_free(block_id);
}

flb_sds_destroy(ref_name);
return FLB_ERROR;
}
Expand All @@ -420,7 +428,6 @@ static int send_blob(struct flb_config *config,
/* For Logs type, we need to commit the block right away */
if (event_type == FLB_EVENT_TYPE_LOGS) {
ret = azb_block_blob_commit_block(ctx, block_id, tag, ms);
flb_free(block_id);
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@brablc brablc Apr 22, 2025

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Isn't it possible, that only removing this line should be enough? Calling flb_free on NULL should not be a problem.

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@leonardo-albertovich leonardo-albertovich Apr 22, 2025

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Just removing that line fixes the double free but considering that there are code paths that lead to calling free with block_id holding NULL it's worth adding the check since older systems (and maybe alternative libc implementations?) don't handle it gracefully.

}
}
else if (ret == CREATE_BLOB) {
Expand All @@ -436,7 +443,10 @@ static int send_blob(struct flb_config *config,
}

flb_sds_destroy(uri);
flb_free(block_id);

if (block_id != NULL) {
flb_free(block_id);
}

return ret;
}
Expand Down Expand Up @@ -593,13 +603,13 @@ static int ensure_container(struct flb_azure_blob *ctx)
else if (status == 200) {
flb_plg_info(ctx->ins, "container '%s' already exists", ctx->container_name);
return FLB_TRUE;
}
}
else if (status == 403) {
flb_plg_error(ctx->ins, "failed getting container '%s', access denied",
ctx->container_name);
return FLB_FALSE;
}

flb_plg_error(ctx->ins, "get container request failed, status=%i",
status);

Expand Down
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