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dmarc=pass (p=quarantine dis=none) header.from=manguebit.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=manguebit.com From: Paulo Alcantara DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=manguebit.com; s=dkim; t=1709910399; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=drUBuRpBrYjImBRIjowgNCrUttKS3pWI4B5MFqZprN4=; b=pv70c0iteBAxZbkmE8ehyOpE9ZQUu2uOs3OvzXqVFTq453coE7cQtKh6k8FWfk9QjtlI0+ dp1QPWBuXYumB3I3TA9HKF8OPoxlXToVZddjOoe28bhaVYcWeP9dXMZ/93Sr6H6LxbYpTq JEIdSVX4erejo7ZNC5k+UcW2hSpZif8oZ+e4JI7LlNzikN9dnl3ZVgaYzJy+EKCGUu5Pj1 lajoe+BXsNT0SEvYeDeoJX+JoYwaHBId3Cku2t4wuXuC5oKqvoxvL/7y+tj34wJplvA4Np S4Wu35GcBrcC+qFuuLJN5YrTTDDV/B8+bBOWScZ2mqW5Gzjv1SqDgbpaUvpngw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=manguebit.com; s=dkim; t=1709910399; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-transfer-encoding:content-transfer-encoding: in-reply-to:references; bh=drUBuRpBrYjImBRIjowgNCrUttKS3pWI4B5MFqZprN4=; b=C1cwhiHIVRSN1gVersQCZWZqW5GbMwkVBBl20QuTeNictd3PJBvN9K92ZhvapH75YIVkje F6GlM++4Nr6IhViDdue+mxbrVC3a7zB67mpOi0doXMXmrOYCHKUotPCF0DSs09TA4JwzYp zkTN8w6EuntyALOcZkxg7ZOsO86AXtuRL9hkpVRpiwX2GaKlPfYhrsiol1xIxz3wGbBs9g +qen15Thp4JEczAH6ScaSx7vwWVs3uxGTDLv55F9MlwI9XyVGosbYiGP/E7AE1pakTyuzg pEnlmApewJ95x3Ob1Wto0fwr9UF/9jmsw85WbQm9gZHm2kwluSQ5yh651jupcA== ARC-Authentication-Results: i=1; ORIGINATING; auth=pass smtp.mailfrom=pc@manguebit.com ARC-Seal: i=1; s=dkim; d=manguebit.com; t=1709910399; a=rsa-sha256; cv=none; b=mq4oqwukXBRAkaIqwIY64y1Ephpefu4s9K0McpoBqXkFMJCG4YEdPbNziiRR3V/6ksTHKC WqX42Y5AzrPucjkZeOeZ0lNS4/2giCx24XtjwWUtumPPGmKJNH1N59ZMnhqaXywwh2jN55 SH/h347rnoovHMaF76KURPGgpnMoHtL3rGE9qEbu6w565Tyxm664FO4S+zBmR4db3aUx8f VvPNQKoAJ8SYGWqlYQYjkebU5/69BgWaEBLCYUh9ENzNmcGrtI9oXEbkIX8jXpHHOOZaLJ Mg6W4zlAwi4XhfNxmZuu7FBEW59PRJq2qvV9N9OKNnKMsPIc9DdIbifGuEnbLQ== To: piastryyy@gmail.com Cc: linux-cifs@vger.kernel.org, Paulo Alcantara Subject: [PATCH] cifs.upcall: fix UAF in get_cachename_from_process_env() Date: Fri, 8 Mar 2024 12:06:15 -0300 Message-ID: <20240308150615.339103-1-pc@manguebit.com> Precedence: bulk X-Mailing-List: linux-cifs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Whether lseek(2) fails or @bufsize * 2 > ENV_BUF_MAX, then @buf would end up being freed twice. For instance: cifs-utils-7.0/cifs.upcall.c:501: freed_arg: "free" frees "buf". cifs-utils-7.0/cifs.upcall.c:524: double_free: Calling "free" frees pointer "buf" which has already been freed. 522| } 523| out_close: 524|-> free(buf); 525| close(fd); 526| return cachename; Fix this by setting @buf to NULL after freeing it to prevent UAF. Fixes: ed97e4ecab4e ("cifs.upcall: allow scraping of KRB5CCNAME out of initiating task's /proc//environ file") Signed-off-by: Paulo Alcantara (Red Hat) --- cifs.upcall.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/cifs.upcall.c b/cifs.upcall.c index 52c03280dbe0..ff6f2bd271bc 100644 --- a/cifs.upcall.c +++ b/cifs.upcall.c @@ -498,10 +498,11 @@ retry: /* We read to the end of the buffer. Double and try again */ syslog(LOG_DEBUG, "%s: read to end of buffer (%zu bytes)\n", __func__, bufsize); - free(buf); - bufsize *= 2; if (lseek(fd, 0, SEEK_SET) < 0) goto out_close; + free(buf); + buf = NULL; + bufsize *= 2; goto retry; }