diff mbox series

[wrynose,1/2] dropbear: add follow-up patches for CVE-2019-6111

Message ID 20261023192914.159339-1-peter.marko@siemens.com
State New
Headers show
Series [wrynose,1/2] dropbear: add follow-up patches for CVE-2019-6111 | expand

Commit Message

Peter Marko Oct. 23, 2026, 7:29 p.m. UTC
From: Peter Marko <peter.marko@siemens.com>

Pick additional patches referencing this CVE from 2026.90 or 2026.91
releases.

Signed-off-by: Peter Marko <peter.marko@siemens.com>
---
 .../dropbear/dropbear/CVE-2019-6111-01.patch  | 364 ++++++++++++++++++
 .../dropbear/dropbear/CVE-2019-6111-02.patch  |  43 +++
 .../dropbear/dropbear/CVE-2019-6111-03.patch  |  34 ++
 .../recipes-core/dropbear/dropbear_2025.89.bb |   3 +
 4 files changed, 444 insertions(+)
 create mode 100644 meta/recipes-core/dropbear/dropbear/CVE-2019-6111-01.patch
 create mode 100644 meta/recipes-core/dropbear/dropbear/CVE-2019-6111-02.patch
 create mode 100644 meta/recipes-core/dropbear/dropbear/CVE-2019-6111-03.patch
diff mbox series

Patch

diff --git a/meta/recipes-core/dropbear/dropbear/CVE-2019-6111-01.patch b/meta/recipes-core/dropbear/dropbear/CVE-2019-6111-01.patch
new file mode 100644
index 0000000000..8e6da5fc23
--- /dev/null
+++ b/meta/recipes-core/dropbear/dropbear/CVE-2019-6111-01.patch
@@ -0,0 +1,364 @@ 
+From 143291baca6ebb3407a0c25c85bd53bf041a6ab7 Mon Sep 17 00:00:00 2001
+From: Matt Johnston <matt@ucc.asn.au>
+Date: Mon, 20 Apr 2026 20:57:11 +0800
+Subject: [PATCH] scp: more CVE-2019-6111 fix
+
+Cherrypicked from OpenSSH portable
+
+commit 3d896c157c722bc47adca51a58dca859225b5874
+djm Sun Feb 10 11:15:52 2019 +0000
+
+upstream: when checking that filenames sent by the server side
+
+match what the client requested, be prepared to handle shell-style brace
+alternations, e.g. "{foo,bar}".
+
+"looks good to me" millert@ + in snaps for the last week courtesy
+deraadt@
+
+CVE: CVE-2019-6111
+Upstream-Status: Backport [https://github.com/mkj/dropbear/commit/143291baca6ebb3407a0c25c85bd53bf041a6ab7]
+Signed-off-by: Peter Marko <peter.marko@siemens.com>
+---
+ src/scp.c | 281 +++++++++++++++++++++++++++++++++++++++++++++++++++---
+ 1 file changed, 269 insertions(+), 12 deletions(-)
+
+diff --git a/src/scp.c b/src/scp.c
+index bf98986c..d151587c 100644
+--- a/src/scp.c
++++ b/src/scp.c
+@@ -74,7 +74,6 @@
+  */
+ 
+ #include "includes.h"
+-/*RCSID("$OpenBSD: scp.c,v 1.130 2006/01/31 10:35:43 djm Exp $");*/
+ 
+ #include <fnmatch.h>
+ 
+@@ -600,6 +599,253 @@ tolocal(int argc, char **argv)
+ 	}
+ }
+ 
++/* Appends a string to an array; returns 0 on success, -1 on alloc failure */
++static int
++append(char *cp, char ***ap, size_t *np)
++{
++	char **tmp;
++
++	if ((tmp = reallocarray(*ap, *np + 1, sizeof(*tmp))) == NULL)
++		return -1;
++	tmp[(*np)] = cp;
++	(*np)++;
++	*ap = tmp;
++	return 0;
++}
++
++/*
++ * Finds the start and end of the first brace pair in the pattern.
++ * returns 0 on success or -1 for invalid patterns.
++ */
++static int
++find_brace(const char *pattern, int *startp, int *endp)
++{
++	int i;
++	int in_bracket, brace_level;
++
++	*startp = *endp = -1;
++	in_bracket = brace_level = 0;
++	for (i = 0; i < INT_MAX && *endp < 0 && pattern[i] != '\0'; i++) {
++		switch (pattern[i]) {
++		case '\\':
++			/* skip next character */
++			if (pattern[i + 1] != '\0')
++				i++;
++			break;
++		case '[':
++			in_bracket = 1;
++			break;
++		case ']':
++			in_bracket = 0;
++			break;
++		case '{':
++			if (in_bracket)
++				break;
++			if (pattern[i + 1] == '}') {
++				/* Protect a single {}, for find(1), like csh */
++				i++; /* skip */
++				break;
++			}
++			if (*startp == -1)
++				*startp = i;
++			brace_level++;
++			break;
++		case '}':
++			if (in_bracket)
++				break;
++			if (*startp < 0) {
++				/* Unbalanced brace */
++				return -1;
++			}
++			if (--brace_level <= 0)
++				*endp = i;
++			break;
++		}
++	}
++	/* unbalanced brackets/braces */
++	if (*endp < 0 && (*startp >= 0 || in_bracket))
++		return -1;
++	return 0;
++}
++
++/*
++ * Assembles and records a successfully-expanded pattern, returns -1 on
++ * alloc failure.
++ */
++static int
++emit_expansion(const char *pattern, int brace_start, int brace_end,
++    int sel_start, int sel_end, char ***patternsp, size_t *npatternsp)
++{
++	char *cp;
++	int o = 0, tail_len = strlen(pattern + brace_end + 1);
++
++	if ((cp = malloc(brace_start + (sel_end - sel_start) +
++	    tail_len + 1)) == NULL)
++		return -1;
++
++	/* Pattern before initial brace */
++	if (brace_start > 0) {
++		memcpy(cp, pattern, brace_start);
++		o = brace_start;
++	}
++	/* Current braced selection */
++	if (sel_end - sel_start > 0) {
++		memcpy(cp + o, pattern + sel_start,
++		    sel_end - sel_start);
++		o += sel_end - sel_start;
++	}
++	/* Remainder of pattern after closing brace */
++	if (tail_len > 0) {
++		memcpy(cp + o, pattern + brace_end + 1, tail_len);
++		o += tail_len;
++	}
++	cp[o] = '\0';
++	if (append(cp, patternsp, npatternsp) != 0) {
++		free(cp);
++		return -1;
++	}
++	return 0;
++}
++
++/*
++ * Expand the first encountered brace in pattern, appending the expanded
++ * patterns it yielded to the *patternsp array.
++ *
++ * Returns 0 on success or -1 on allocation failure.
++ *
++ * Signals whether expansion was performed via *expanded and whether
++ * pattern was invalid via *invalid.
++ */
++static int
++brace_expand_one(const char *pattern, char ***patternsp, size_t *npatternsp,
++    int *expanded, int *invalid)
++{
++	int i;
++	int in_bracket, brace_start, brace_end, brace_level;
++	int sel_start, sel_end;
++
++	*invalid = *expanded = 0;
++
++	if (find_brace(pattern, &brace_start, &brace_end) != 0) {
++		*invalid = 1;
++		return 0;
++	} else if (brace_start == -1)
++		return 0;
++
++	in_bracket = brace_level = 0;
++	for (i = sel_start = brace_start + 1; i < brace_end; i++) {
++		switch (pattern[i]) {
++		case '{':
++			if (in_bracket)
++				break;
++			brace_level++;
++			break;
++		case '}':
++			if (in_bracket)
++				break;
++			brace_level--;
++			break;
++		case '[':
++			in_bracket = 1;
++			break;
++		case ']':
++			in_bracket = 0;
++			break;
++		case '\\':
++			if (i < brace_end - 1)
++				i++; /* skip */
++			break;
++		}
++		if (pattern[i] == ',' || i == brace_end - 1) {
++			if (in_bracket || brace_level > 0)
++				continue;
++			/* End of a selection, emit an expanded pattern */
++
++			/* Adjust end index for last selection */
++			sel_end = (i == brace_end - 1) ? brace_end : i;
++			if (emit_expansion(pattern, brace_start, brace_end,
++			    sel_start, sel_end, patternsp, npatternsp) != 0)
++				return -1;
++			/* move on to the next selection */
++			sel_start = i + 1;
++			continue;
++		}
++	}
++	if (in_bracket || brace_level > 0) {
++		*invalid = 1;
++		return 0;
++	}
++	/* success */
++	*expanded = 1;
++	return 0;
++}
++
++/* Expand braces from pattern. Returns 0 on success, -1 on failure */
++static int
++brace_expand(const char *pattern, char ***patternsp, size_t *npatternsp)
++{
++	char *cp, *cp2, **active = NULL, **done = NULL;
++	size_t i, nactive = 0, ndone = 0;
++	int ret = -1, invalid = 0, expanded = 0;
++
++	*patternsp = NULL;
++	*npatternsp = 0;
++
++	/* Start the worklist with the original pattern */
++	if ((cp = strdup(pattern)) == NULL)
++		return -1;
++	if (append(cp, &active, &nactive) != 0) {
++		free(cp);
++		return -1;
++	}
++	while (nactive > 0) {
++		cp = active[nactive - 1];
++		nactive--;
++		if (brace_expand_one(cp, &active, &nactive,
++		    &expanded, &invalid) == -1) {
++			free(cp);
++			goto fail;
++		}
++		if (invalid)
++			fatal("%s: invalid brace pattern \"%s\"", __func__, cp);
++		if (expanded) {
++			/*
++			 * Current entry expanded to new entries on the
++			 * active list; discard the progenitor pattern.
++			 */
++			free(cp);
++			continue;
++		}
++		/*
++		 * Pattern did not expand; append the finename component to
++		 * the completed list
++		 */
++		if ((cp2 = strrchr(cp, '/')) != NULL)
++			*cp2++ = '\0';
++		else
++			cp2 = cp;
++		if (append(xstrdup(cp2), &done, &ndone) != 0) {
++			free(cp);
++			goto fail;
++		}
++		free(cp);
++	}
++	/* success */
++	*patternsp = done;
++	*npatternsp = ndone;
++	done = NULL;
++	ndone = 0;
++	ret = 0;
++ fail:
++	for (i = 0; i < nactive; i++)
++		free(active[i]);
++	free(active);
++	for (i = 0; i < ndone; i++)
++		free(done[i]);
++	free(done);
++	return ret;
++}
++
+ void
+ source(int argc, char **argv)
+ {
+@@ -841,7 +1087,8 @@ sink(int argc, char **argv, const char *src)
+ 	off_t size, statbytes;
+ 	int setimes, targisdir, wrerrno = 0;
+ 	char ch, *cp, *np, *targ, *why, *vect[1], buf[2048];
+-	char *src_copy = NULL, *restrict_pattern = NULL;
++	char **patterns = NULL;
++	size_t n, npatterns = 0;
+ 	struct timeval tv[2];
+ 
+ #define	atime	tv[0]
+@@ -868,16 +1115,13 @@ sink(int argc, char **argv, const char *src)
+ 		 * Prepare to try to restrict incoming filenames to match
+ 		 * the requested destination file glob.
+ 		 */
+-		if ((src_copy = strdup(src)) == NULL)
+-			fatal("strdup failed");
+-		if ((restrict_pattern = strrchr(src_copy, '/')) != NULL) {
+-			*restrict_pattern++ = '\0';
+-		}
++		if (brace_expand(src, &patterns, &npatterns) != 0)
++			fatal("%s: could not expand pattern", __func__);
+ 	}
+ 	for (first = 1;; first = 0) {
+ 		cp = buf;
+ 		if (atomicio(read, remin, cp, 1) != 1)
+-			return;
++			goto done;
+ 		if (*cp++ == '\n')
+ 			SCREWUP("unexpected <newline>");
+ 		do {
+@@ -900,7 +1144,7 @@ sink(int argc, char **argv, const char *src)
+ 		}
+ 		if (buf[0] == 'E') {
+ 			(void) atomicio(vwrite, remout, "", 1);
+-			return;
++			goto done;
+ 		}
+ 		if (ch == '\n')
+ 			*--cp = 0;
+@@ -956,9 +1200,14 @@ sink(int argc, char **argv, const char *src)
+ 			run_err("error: unexpected filename: %s", cp);
+ 			exit(1);
+ 		}
+-		if (restrict_pattern != NULL &&
+-		    fnmatch(restrict_pattern, cp, 0) != 0)
+-			SCREWUP("filename does not match request");
++		if (npatterns > 0) {
++			for (n = 0; n < npatterns; n++) {
++				if (fnmatch(patterns[n], cp, 0) == 0)
++					break;
++			}
++			if (n >= npatterns)
++				SCREWUP("filename does not match request");
++		}
+ 		if (targisdir) {
+ 			static char *namebuf = NULL;
+ 			static size_t cursize = 0;
+@@ -1123,7 +1372,15 @@ bad:			run_err("%s: %s", np, strerror(errno));
+ 			break;
+ 		}
+ 	}
++done:
++	for (n = 0; n < npatterns; n++)
++		free(patterns[n]);
++	free(patterns);
++	return;
+ screwup:
++	for (n = 0; n < npatterns; n++)
++		free(patterns[n]);
++	free(patterns);
+ 	run_err("protocol error: %s", why);
+ 	exit(1);
+ }
diff --git a/meta/recipes-core/dropbear/dropbear/CVE-2019-6111-02.patch b/meta/recipes-core/dropbear/dropbear/CVE-2019-6111-02.patch
new file mode 100644
index 0000000000..99819b732a
--- /dev/null
+++ b/meta/recipes-core/dropbear/dropbear/CVE-2019-6111-02.patch
@@ -0,0 +1,43 @@ 
+From 61bd0e3e6573277de17359763aa5827a189c8d7f Mon Sep 17 00:00:00 2001
+From: Matt Johnston <matt@ucc.asn.au>
+Date: Sat, 2 May 2026 08:43:26 +0800
+Subject: [PATCH] scp: Disallow -r to an existing directory
+
+Checks of received paths don't catch all cases in -r recursive mode, so
+disallow -r when the destination directory exists. This mitigates
+CVE-2019-6111, where unexpected files would be accepted from a malicious
+scp server.
+
+Alternatives like rsync could be used in that case.
+
+The new error message may be misleading if parent path components of the
+destination are also missing, though the command would have failed
+regardless.
+
+CVE: CVE-2019-6111
+Upstream-Status: Backport [https://github.com/mkj/dropbear/commit/61bd0e3e6573277de17359763aa5827a189c8d7f]
+Signed-off-by: Peter Marko <peter.marko@siemens.com>
+---
+ src/scp.c | 9 +++++++++
+ 1 file changed, 9 insertions(+)
+
+diff --git a/src/scp.c b/src/scp.c
+index d151587c..09297a5b 100644
+--- a/src/scp.c
++++ b/src/scp.c
+@@ -583,6 +583,15 @@ tolocal(int argc, char **argv)
+ 			if (*suser == '\0')
+ 				suser = NULL;
+ 		}
++
++		char *dest = *(argv + argc - 1);
++		if (!(access(dest, F_OK) == 0 && errno == ENOENT)) {
++			/* paths sent from the server in recursive mode aren't adequately
++			 * checked that they match the requested files, so disallow this */
++			fprintf(stderr, "-r destination \"%s\" must not already exist\n", dest);
++			exit(1);
++		}
++
+ 		host = cleanhostname(host);
+ 		len = strlen(src) + CMDNEEDS + 20;
+ 		bp = xmalloc(len);
diff --git a/meta/recipes-core/dropbear/dropbear/CVE-2019-6111-03.patch b/meta/recipes-core/dropbear/dropbear/CVE-2019-6111-03.patch
new file mode 100644
index 0000000000..c70bf4bb68
--- /dev/null
+++ b/meta/recipes-core/dropbear/dropbear/CVE-2019-6111-03.patch
@@ -0,0 +1,34 @@ 
+From 0c5629a5d543ef5e4eff43345b1eedf2afef84ca Mon Sep 17 00:00:00 2001
+From: Matt Johnston <matt@ucc.asn.au>
+Date: Mon, 4 May 2026 21:35:57 +0800
+Subject: [PATCH] scp: don't use reallocarray
+
+reallocarray() isn't portable. An overflow check can be used instead.
+
+Fixes: 143291baca6e ("scp: more CVE-2019-6111 fix")
+
+CVE: CVE-2019-6111
+Upstream-Status: Backport [https://github.com/mkj/dropbear/commit/0c5629a5d543ef5e4eff43345b1eedf2afef84ca]
+Signed-off-by: Peter Marko <peter.marko@siemens.com>
+---
+ src/scp.c | 7 ++++++-
+ 1 file changed, 6 insertions(+), 1 deletion(-)
+
+diff --git a/src/scp.c b/src/scp.c
+index e5ce4e2f..2f7a6279 100644
+--- a/src/scp.c
++++ b/src/scp.c
+@@ -614,7 +614,12 @@ append(char *cp, char ***ap, size_t *np)
+ {
+ 	char **tmp;
+ 
+-	if ((tmp = reallocarray(*ap, *np + 1, sizeof(*tmp))) == NULL)
++	if (*np + 1 > (SIZE_MAX / sizeof(*tmp))) {
++		/* overflow */
++		return -1;
++	}
++
++	if ((tmp = realloc(*ap, (*np + 1) * sizeof(*tmp))) == NULL)
+ 		return -1;
+ 	tmp[(*np)] = cp;
+ 	(*np)++;
diff --git a/meta/recipes-core/dropbear/dropbear_2025.89.bb b/meta/recipes-core/dropbear/dropbear_2025.89.bb
index 685ecf9a1b..17f8a1ab3f 100644
--- a/meta/recipes-core/dropbear/dropbear_2025.89.bb
+++ b/meta/recipes-core/dropbear/dropbear_2025.89.bb
@@ -25,6 +25,9 @@  SRC_URI = "http://matt.ucc.asn.au/dropbear/releases/dropbear-${PV}.tar.bz2 \
            file://dropbear.socket \
            file://dropbear.default \
            ${@bb.utils.contains('DISTRO_FEATURES', 'pam', '${PAM_SRC_URI}', '', d)} \
+           file://CVE-2019-6111-01.patch \
+           file://CVE-2019-6111-02.patch \
+           file://CVE-2019-6111-03.patch \
            "
 
 SRC_URI[sha256sum] = "0d1f7ca711cfc336dc8a85e672cab9cfd8223a02fe2da0a4a7aeb58c9e113634"