From mboxrd@z Thu Jan 1 00:00:00 1970 From: Yann E. MORIN Date: Sat, 27 Feb 2021 09:20:08 +0100 Subject: [Buildroot] [PATCH] package/screen: add security fix for CVE-2021-26937 In-Reply-To: <20210226232256.25046-1-peter@korsgaard.com> References: <20210226232256.25046-1-peter@korsgaard.com> Message-ID: <20210227082008.GE2390841@scaer> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: buildroot@busybox.net Peter, All, On 2021-02-27 00:22 +0100, Peter Korsgaard spake thusly: > encoding.c in GNU Screen through 4.8.0 allows remote attackers to cause a > denial of service (invalid write access and application crash) or possibly > have unspecified other impact via a crafted UTF-8 character sequence. > > For more details, see the oss-security discussion: > https://www.openwall.com/lists/oss-security/2021/02/09/3 > > So far no fix has been added to upstream git, and a number of early proposed > fixes caused regressions, so pull the security fix from the screen 4.8.0-5 > Debian package. > > Signed-off-by: Peter Korsgaard Applied to master, thanks. Regards, Yann E. MORIN. > --- > package/screen/0008_CVE-2021-26937.patch | 68 ++++++++++++++++++++++++ > package/screen/screen.mk | 3 ++ > 2 files changed, 71 insertions(+) > create mode 100644 package/screen/0008_CVE-2021-26937.patch > > diff --git a/package/screen/0008_CVE-2021-26937.patch b/package/screen/0008_CVE-2021-26937.patch > new file mode 100644 > index 0000000000..df7efa0294 > --- /dev/null > +++ b/package/screen/0008_CVE-2021-26937.patch > @@ -0,0 +1,68 @@ > +Description: [CVE-2021-26937] Fix out of bounds array access > +Author: Michael Schr?der > +Bug-Debian: https://bugs.debian.org/982435 > +Bug: https://savannah.gnu.org/bugs/?60030 > +Bug: https://lists.gnu.org/archive/html/screen-devel/2021-02/msg00000.html > +Bug-OSS-Security: https://www.openwall.com/lists/oss-security/2021/02/09/3 > +Origin: https://lists.gnu.org/archive/html/screen-devel/2021-02/msg00010.html > + > +Downloaded from Debian: > +https://sources.debian.org/data/main/s/screen/4.8.0-5/debian/patches/99_CVE-2021-26937.patch > + > +Signed-off-by: Peter Korsgaard > +--- a/encoding.c > ++++ b/encoding.c > +@@ -43,7 +43,7 @@ > + # ifdef UTF8 > + static int recode_char __P((int, int, int)); > + static int recode_char_to_encoding __P((int, int)); > +-static void comb_tofront __P((int, int)); > ++static void comb_tofront __P((int)); > + # ifdef DW_CHARS > + static int recode_char_dw __P((int, int *, int, int)); > + static int recode_char_dw_to_encoding __P((int, int *, int)); > +@@ -1263,6 +1263,8 @@ > + {0x30000, 0x3FFFD}, > + }; > + > ++ if (c >= 0xdf00 && c <= 0xdfff) > ++ return 1; /* dw combining sequence */ > + return ((bisearch(c, wide, sizeof(wide) / sizeof(struct interval) - 1)) || > + (cjkwidth && > + bisearch(c, ambiguous, > +@@ -1330,11 +1332,12 @@ > + } > + > + static void > +-comb_tofront(root, i) > +-int root, i; > ++comb_tofront(i) > ++int i; > + { > + for (;;) > + { > ++ int root = i >= 0x700 ? 0x801 : 0x800; > + debug1("bring to front: %x\n", i); > + combchars[combchars[i]->prev]->next = combchars[i]->next; > + combchars[combchars[i]->next]->prev = combchars[i]->prev; > +@@ -1396,9 +1399,9 @@ > + { > + /* full, recycle old entry */ > + if (c1 >= 0xd800 && c1 < 0xe000) > +- comb_tofront(root, c1 - 0xd800); > ++ comb_tofront(c1 - 0xd800); > + i = combchars[root]->prev; > +- if (c1 == i + 0xd800) > ++ if (i == 0x800 || i == 0x801 || c1 == i + 0xd800) > + { > + /* completely full, can't recycle */ > + debug("utf8_handle_comp: completely full!\n"); > +@@ -1422,7 +1425,7 @@ > + mc->font = (i >> 8) + 0xd8; > + mc->fontx = 0; > + debug3("combinig char %x %x -> %x\n", c1, c, i + 0xd800); > +- comb_tofront(root, i); > ++ comb_tofront(i); > + } > + > + #else /* !UTF8 */ > diff --git a/package/screen/screen.mk b/package/screen/screen.mk > index c24067440e..f75f92cb47 100644 > --- a/package/screen/screen.mk > +++ b/package/screen/screen.mk > @@ -15,6 +15,9 @@ SCREEN_CONF_ENV = CFLAGS="$(TARGET_CFLAGS)" > SCREEN_CONF_OPTS = --enable-colors256 > SCREEN_INSTALL_TARGET_OPTS = DESTDIR=$(TARGET_DIR) SCREEN=screen install_bin > > +# 0008_CVE-2021-26937.patch > +SCREEN_IGNORE_CVES += CVE-2021-26937 > + > ifeq ($(BR2_PACKAGE_LINUX_PAM),y) > SCREEN_DEPENDENCIES += linux-pam > SCREEN_CONF_OPTS += --enable-pam > -- > 2.20.1 > > _______________________________________________ > buildroot mailing list > buildroot at busybox.net > http://lists.busybox.net/mailman/listinfo/buildroot -- .-----------------.--------------------.------------------.--------------------. | Yann E. MORIN | Real-Time Embedded | /"\ ASCII RIBBON | Erics' conspiracy: | | +33 662 376 056 | Software Designer | \ / CAMPAIGN | ___ | | +33 561 099 427 `------------.-------: X AGAINST | \e/ There is no | | http://ymorin.is-a-geek.org/ | _/*\_ | / \ HTML MAIL | v conspiracy. | '------------------------------^-------^------------------^--------------------'