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Add upstream patch to fix "Attempt to allocate 0 bytes" errors while scanning

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certain PDFs
This commit is contained in:
Orion Poplawski 2020-05-02 07:33:48 -06:00 committed by Sérgio M. Basto
parent 2ab3499bfd
commit 47c82af727
2 changed files with 97 additions and 1 deletions
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89
0e865c4f0e5ea5c4879681d843a9b93fc871fd90.patch Normal file
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@ -0,0 +1,89 @@
From 0e865c4f0e5ea5c4879681d843a9b93fc871fd90 Mon Sep 17 00:00:00 2001
From: "Micah Snyder (micasnyd)" <micasnyd@cisco.com>
Date: Mon, 6 Apr 2020 15:03:20 -0700
Subject: [PATCH] PDF: Fix error Attempt to allocate 0 bytes
The PDF parser currently prints verbose error messages when attempting
to shrink a buffer down to actual data length after decoding if it turns
out that the decoded stream was empty (0 bytes). With exception to the
verbose error messages, there's no real behavior issue.
This commit fixes the issue by checking if any bytes were decoded before
attempting to shrink the buffer.
---
libclamav/pdfdecode.c | 27 ++++++++++++++++++---------
1 file changed, 18 insertions(+), 9 deletions(-)
diff --git a/libclamav/pdfdecode.c b/libclamav/pdfdecode.c
index 8315f3a761..d63f7b1cd4 100644
--- a/libclamav/pdfdecode.c
+++ b/libclamav/pdfdecode.c
@@ -638,8 +638,11 @@ static cl_error_t filter_rldecode(struct pdf_struct *pdf, struct pdf_obj *obj, s
}
if (rc == CL_SUCCESS) {
- /* Shrink output buffer to final the decoded data length to minimize RAM usage */
- if (!(temp = cli_realloc(decoded, declen))) {
+ if (declen == 0) {
+ cli_dbgmsg("cli_pdf: empty stream after inflation completed.\n");
+ rc = CL_BREAK;
+ } else if (!(temp = cli_realloc(decoded, declen))) {
+ /* Shrink output buffer to final the decoded data length to minimize RAM usage */
cli_errmsg("cli_pdf: cannot reallocate memory for decoded output\n");
rc = CL_EMEM;
} else {
@@ -647,7 +650,7 @@ static cl_error_t filter_rldecode(struct pdf_struct *pdf, struct pdf_obj *obj, s
}
}
- if (rc == CL_SUCCESS) {
+ if (rc == CL_SUCCESS || rc == CL_BREAK) {
free(token->content);
cli_dbgmsg("cli_pdf: decoded %lu bytes from %lu total bytes\n",
@@ -817,8 +820,11 @@ static cl_error_t filter_flatedecode(struct pdf_struct *pdf, struct pdf_obj *obj
(void)inflateEnd(&stream);
if (rc == CL_SUCCESS) {
- /* Shrink output buffer to final the decoded data length to minimize RAM usage */
- if (!(temp = cli_realloc(decoded, declen))) {
+ if (declen == 0) {
+ cli_dbgmsg("cli_pdf: empty stream after inflation completed.\n");
+ rc = CL_BREAK;
+ } else if (!(temp = cli_realloc(decoded, declen))) {
+ /* Shrink output buffer to final the decoded data length to minimize RAM usage */
cli_errmsg("cli_pdf: cannot reallocate memory for decoded output\n");
rc = CL_EMEM;
} else {
@@ -826,7 +832,7 @@ static cl_error_t filter_flatedecode(struct pdf_struct *pdf, struct pdf_obj *obj
}
}
- if (rc == CL_SUCCESS) {
+ if (rc == CL_SUCCESS || rc == CL_BREAK) {
free(token->content);
token->content = decoded;
@@ -1099,8 +1105,11 @@ static cl_error_t filter_lzwdecode(struct pdf_struct *pdf, struct pdf_obj *obj,
(void)lzwInflateEnd(&stream);
if (rc == CL_SUCCESS) {
- /* Shrink output buffer to final the decoded data length to minimize RAM usage */
- if (!(temp = cli_realloc(decoded, declen))) {
+ if (declen == 0) {
+ cli_dbgmsg("cli_pdf: empty stream after inflation completed.\n");
+ rc = CL_BREAK;
+ } else if (!(temp = cli_realloc(decoded, declen))) {
+ /* Shrink output buffer to final the decoded data length to minimize RAM usage */
cli_errmsg("cli_pdf: cannot reallocate memory for decoded output\n");
rc = CL_EMEM;
} else {
@@ -1108,7 +1117,7 @@ static cl_error_t filter_lzwdecode(struct pdf_struct *pdf, struct pdf_obj *obj,
}
}
- if (rc == CL_SUCCESS) {
+ if (rc == CL_SUCCESS || rc == CL_BREAK) {
free(token->content);
token->content = decoded;

9
clamav.spec
View File

@ -41,7 +41,7 @@
Summary: End-user tools for the Clam Antivirus scanner
Name: clamav
Version: 0.102.2
Release: 8%{?dist}
Release: 9%{?dist}
License: %{?with_unrar:proprietary}%{!?with_unrar:GPLv2}
URL: https://www.clamav.net/
%if %{with unrar}
@ -91,6 +91,8 @@ Patch1: clamav-default_confs.patch
Patch2: clamav-0.99-private.patch
# Patch to use EL7 libcurl
Patch3: clamav-curl.patch
# Upstream fix for "Attempt to allocate 0 bytes" while scanning PDFs
Patch4: https://github.com/Cisco-Talos/clamav-devel/commit/0e865c4f0e5ea5c4879681d843a9b93fc871fd90.patch
BuildRequires: autoconf automake gettext-devel libtool libtool-ltdl-devel
BuildRequires: gcc-c++
@ -253,6 +255,7 @@ This package contains files which are needed to run the clamav-milter.
%patch2 -p1 -b .private
# Patch to use older libcurl
%{?el7:%patch3 -p1 -b .curl}
%patch4 -p1 -b .pdf
install -p -m0644 %SOURCE300 clamav-milter/
@ -615,6 +618,10 @@ fi
%changelog
* Sat May 02 2020 Orion Poplawski <orion@nwra.com> - 0.102.2-9
- Add upstream patch to fix "Attempt to allocate 0 bytes" errors while scanning
certain PDFs
* Thu Apr 30 2020 Orion Poplawski <orion@nwra.com> - 0.102.2-8
- Enable prelude support (bz#1829726)