From: Pavel Zhukov <[email protected]> A NULL pointer dereference in Busybox's hush applet leads to denial of service when processing a crafted shell command, due to missing validation after a \x03 delimiter character. This may be used for DoS under very rare conditions of filtered command input.
Reference: https://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2021-42376 Signed-off-by: Pavel Zhukov <[email protected]> --- .../busybox/busybox/CVE-2021-42376.patch | 138 ++++++++++++++++++ meta/recipes-core/busybox/busybox_1.31.1.bb | 1 + 2 files changed, 139 insertions(+) create mode 100644 meta/recipes-core/busybox/busybox/CVE-2021-42376.patch diff --git a/meta/recipes-core/busybox/busybox/CVE-2021-42376.patch b/meta/recipes-core/busybox/busybox/CVE-2021-42376.patch new file mode 100644 index 0000000000..c913eaee9c --- /dev/null +++ b/meta/recipes-core/busybox/busybox/CVE-2021-42376.patch @@ -0,0 +1,138 @@ +From 56a335378ac100d51c30b21eee499a2effa37fba Mon Sep 17 00:00:00 2001 +From: Denys Vlasenko <[email protected]> +Date: Tue, 15 Jun 2021 16:05:57 +0200 +Subject: hush: fix handling of \^C and "^C" + +function old new delta +parse_stream 2238 2252 +14 +encode_string 243 256 +13 +------------------------------------------------------------------------------ +(add/remove: 0/0 grow/shrink: 2/0 up/down: 27/0) Total: 27 bytes + +Signed-off-by: Denys Vlasenko <[email protected]> +(cherry picked from commit 1b7a9b68d0e9aa19147d7fda16eb9a6b54156985) + +Signed-off-by: Pavel Zhukov <[email protected]> + +CVE: CVE-2021-42376 +Upstream-Status: Backport [https://git.busybox.net/busybox/patch/?id=56a335378ac100d51c30b21eee499a2effa37fba] +Comment: No changes in any hunk +--- + shell/ash_test/ash-misc/control_char3.right | 1 + + shell/ash_test/ash-misc/control_char3.tests | 2 ++ + shell/ash_test/ash-misc/control_char4.right | 1 + + shell/ash_test/ash-misc/control_char4.tests | 2 ++ + shell/hush.c | 11 +++++++++++ + shell/hush_test/hush-misc/control_char3.right | 1 + + shell/hush_test/hush-misc/control_char3.tests | 2 ++ + shell/hush_test/hush-misc/control_char4.right | 1 + + shell/hush_test/hush-misc/control_char4.tests | 2 ++ + 9 files changed, 23 insertions(+) + create mode 100644 shell/ash_test/ash-misc/control_char3.right + create mode 100755 shell/ash_test/ash-misc/control_char3.tests + create mode 100644 shell/ash_test/ash-misc/control_char4.right + create mode 100755 shell/ash_test/ash-misc/control_char4.tests + create mode 100644 shell/hush_test/hush-misc/control_char3.right + create mode 100755 shell/hush_test/hush-misc/control_char3.tests + create mode 100644 shell/hush_test/hush-misc/control_char4.right + create mode 100755 shell/hush_test/hush-misc/control_char4.tests + +diff --git a/shell/ash_test/ash-misc/control_char3.right b/shell/ash_test/ash-misc/control_char3.right +new file mode 100644 +index 000000000..283e02cbb +--- /dev/null ++++ b/shell/ash_test/ash-misc/control_char3.right +@@ -0,0 +1 @@ ++SHELL: line 1: : not found +diff --git a/shell/ash_test/ash-misc/control_char3.tests b/shell/ash_test/ash-misc/control_char3.tests +new file mode 100755 +index 000000000..4359db3f3 +--- /dev/null ++++ b/shell/ash_test/ash-misc/control_char3.tests +@@ -0,0 +1,2 @@ ++# (set argv0 to "SHELL" to avoid "/path/to/shell: blah" in error messages) ++$THIS_SH -c '\' SHELL +diff --git a/shell/ash_test/ash-misc/control_char4.right b/shell/ash_test/ash-misc/control_char4.right +new file mode 100644 +index 000000000..2bf18e684 +--- /dev/null ++++ b/shell/ash_test/ash-misc/control_char4.right +@@ -0,0 +1 @@ ++SHELL: line 1: -: not found +diff --git a/shell/ash_test/ash-misc/control_char4.tests b/shell/ash_test/ash-misc/control_char4.tests +new file mode 100755 +index 000000000..48010f154 +--- /dev/null ++++ b/shell/ash_test/ash-misc/control_char4.tests +@@ -0,0 +1,2 @@ ++# (set argv0 to "SHELL" to avoid "/path/to/shell: blah" in error messages) ++$THIS_SH -c '"-"' SHELL +diff --git a/shell/hush.c b/shell/hush.c +index 9fead37da..249728b9d 100644 +--- a/shell/hush.c ++++ b/shell/hush.c +@@ -5235,6 +5235,11 @@ static int encode_string(o_string *as_string, + } + #endif + o_addQchr(dest, ch); ++ if (ch == SPECIAL_VAR_SYMBOL) { ++ /* Convert "^C" to corresponding special variable reference */ ++ o_addchr(dest, SPECIAL_VAR_QUOTED_SVS); ++ o_addchr(dest, SPECIAL_VAR_SYMBOL); ++ } + goto again; + #undef as_string + } +@@ -5346,6 +5351,11 @@ static struct pipe *parse_stream(char **pstring, + if (ch == '\n') + continue; /* drop \<newline>, get next char */ + nommu_addchr(&ctx.as_string, '\\'); ++ if (ch == SPECIAL_VAR_SYMBOL) { ++ nommu_addchr(&ctx.as_string, ch); ++ /* Convert \^C to corresponding special variable reference */ ++ goto case_SPECIAL_VAR_SYMBOL; ++ } + o_addchr(&ctx.word, '\\'); + if (ch == EOF) { + /* Testcase: eval 'echo Ok\' */ +@@ -5670,6 +5680,7 @@ static struct pipe *parse_stream(char **pstring, + /* Note: nommu_addchr(&ctx.as_string, ch) is already done */ + + switch (ch) { ++ case_SPECIAL_VAR_SYMBOL: + case SPECIAL_VAR_SYMBOL: + /* Convert raw ^C to corresponding special variable reference */ + o_addchr(&ctx.word, SPECIAL_VAR_SYMBOL); +diff --git a/shell/hush_test/hush-misc/control_char3.right b/shell/hush_test/hush-misc/control_char3.right +new file mode 100644 +index 000000000..94b4f8699 +--- /dev/null ++++ b/shell/hush_test/hush-misc/control_char3.right +@@ -0,0 +1 @@ ++hush: can't execute '': No such file or directory +diff --git a/shell/hush_test/hush-misc/control_char3.tests b/shell/hush_test/hush-misc/control_char3.tests +new file mode 100755 +index 000000000..4359db3f3 +--- /dev/null ++++ b/shell/hush_test/hush-misc/control_char3.tests +@@ -0,0 +1,2 @@ ++# (set argv0 to "SHELL" to avoid "/path/to/shell: blah" in error messages) ++$THIS_SH -c '\' SHELL +diff --git a/shell/hush_test/hush-misc/control_char4.right b/shell/hush_test/hush-misc/control_char4.right +new file mode 100644 +index 000000000..698e21427 +--- /dev/null ++++ b/shell/hush_test/hush-misc/control_char4.right +@@ -0,0 +1 @@ ++hush: can't execute '-': No such file or directory +diff --git a/shell/hush_test/hush-misc/control_char4.tests b/shell/hush_test/hush-misc/control_char4.tests +new file mode 100755 +index 000000000..48010f154 +--- /dev/null ++++ b/shell/hush_test/hush-misc/control_char4.tests +@@ -0,0 +1,2 @@ ++# (set argv0 to "SHELL" to avoid "/path/to/shell: blah" in error messages) ++$THIS_SH -c '"-"' SHELL +-- +cgit v1.2.3 + diff --git a/meta/recipes-core/busybox/busybox_1.31.1.bb b/meta/recipes-core/busybox/busybox_1.31.1.bb index 55c00eb483..14ac710f3b 100644 --- a/meta/recipes-core/busybox/busybox_1.31.1.bb +++ b/meta/recipes-core/busybox/busybox_1.31.1.bb @@ -53,6 +53,7 @@ SRC_URI = "https://busybox.net/downloads/busybox-${PV}.tar.bz2;name=tarball \ file://0001-decompress_gunzip-Fix-DoS-if-gzip-is-corrupt.patch \ file://0001-mktemp-add-tmpdir-option.patch \ file://CVE-2021-42374.patch \ + file://CVE-2021-42376.patch \ " SRC_URI_append_libc-musl = " file://musl.cfg " -- 2.34.0
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