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* [PATCH v2] proc: fix /proc/*/map_files lookup some more
@ 2018-03-03 21:51 Alexey Dobriyan
  2018-03-04 20:53 ` Cyrill Gorcunov
  0 siblings, 1 reply; 6+ messages in thread
From: Alexey Dobriyan @ 2018-03-03 21:51 UTC (permalink / raw)
  To: akpm; +Cc: linux-kernel, xemul, gorcunov

I totally forgot that _parse_integer() accepts arbitrary amount of
leading zeroes leading to the following lookups:

		OK
	# readlink /proc/1/map_files/56427ecba000-56427eddc000
	/lib/systemd/systemd

		bogus
	# readlink /proc/1/map_files/00000000000056427ecba000-56427eddc000
	/lib/systemd/systemd
	# readlink /proc/1/map_files/56427ecba000-00000000000056427eddc000
	/lib/systemd/systemd

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
---

 fs/proc/base.c                                         |    4 
 tools/testing/selftests/proc/.gitignore                |    4 
 tools/testing/selftests/proc/Makefile                  |    2 
 tools/testing/selftests/proc/proc-self-map-files-001.c |   82 ++++++++++++++++
 tools/testing/selftests/proc/proc-self-map-files-002.c |   85 +++++++++++++++++
 5 files changed, 176 insertions(+), 1 deletion(-)

--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -1916,6 +1916,8 @@ static int dname_to_vma_addr(struct dentry *dentry,
 	unsigned long long sval, eval;
 	unsigned int len;
 
+	if (str[0] == '0' && str[1] != '-')
+		return -EINVAL;
 	len = _parse_integer(str, 16, &sval);
 	if (len & KSTRTOX_OVERFLOW)
 		return -EINVAL;
@@ -1927,6 +1929,8 @@ static int dname_to_vma_addr(struct dentry *dentry,
 		return -EINVAL;
 	str++;
 
+	if (str[0] == '0' && str[1])
+		return -EINVAL;
 	len = _parse_integer(str, 16, &eval);
 	if (len & KSTRTOX_OVERFLOW)
 		return -EINVAL;
--- a/tools/testing/selftests/proc/.gitignore
+++ b/tools/testing/selftests/proc/.gitignore
@@ -1,2 +1,4 @@
-/proc-self-mem
+/proc-self-map-files-001
+/proc-self-map-files-002
 /proc-self-syscall
+/proc-self-wchan
--- a/tools/testing/selftests/proc/Makefile
+++ b/tools/testing/selftests/proc/Makefile
@@ -1,6 +1,8 @@
 CFLAGS += -Wall -O2
 
 TEST_GEN_PROGS :=
+TEST_GEN_PROGS += proc-self-map-files-001
+TEST_GEN_PROGS += proc-self-map-files-002
 TEST_GEN_PROGS += proc-self-syscall
 TEST_GEN_PROGS += proc-self-wchan
 
new file mode 100644
--- /dev/null
+++ b/tools/testing/selftests/proc/proc-self-map-files-001.c
@@ -0,0 +1,82 @@
+/*
+ * Copyright © 2018 Alexey Dobriyan <adobriyan@gmail.com>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+/* Test readlink /proc/self/map_files/... */
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <sys/mman.h>
+#include <stdlib.h>
+
+static void pass(const char *fmt, unsigned long a, unsigned long b)
+{
+	char name[64];
+	char buf[64];
+
+	snprintf(name, sizeof(name), fmt, a, b);
+	if (readlink(name, buf, sizeof(buf)) == -1)
+		exit(1);
+}
+
+static void fail(const char *fmt, unsigned long a, unsigned long b)
+{
+	char name[64];
+	char buf[64];
+
+	snprintf(name, sizeof(name), fmt, a, b);
+	if (readlink(name, buf, sizeof(buf)) == -1 && errno == ENOENT)
+		return;
+	exit(1);
+}
+
+int main(void)
+{
+	const unsigned int PAGE_SIZE = sysconf(_SC_PAGESIZE);
+	void *p;
+	int fd;
+	unsigned long a, b;
+
+	fd = open("/dev/zero", O_RDONLY);
+	if (fd == -1)
+		return 1;
+
+	p = mmap(NULL, PAGE_SIZE, PROT_NONE, MAP_PRIVATE|MAP_FILE, fd, 0);
+	if (p == MAP_FAILED)
+		return 1;
+
+	a = (unsigned long)p;
+	b = (unsigned long)p + PAGE_SIZE;
+
+	pass("/proc/self/map_files/%lx-%lx", a, b);
+	fail("/proc/self/map_files/ %lx-%lx", a, b);
+	fail("/proc/self/map_files/%lx -%lx", a, b);
+	fail("/proc/self/map_files/%lx- %lx", a, b);
+	fail("/proc/self/map_files/%lx-%lx ", a, b);
+	fail("/proc/self/map_files/0%lx-%lx", a, b);
+	fail("/proc/self/map_files/%lx-0%lx", a, b);
+	if (sizeof(long) == 4) {
+		fail("/proc/self/map_files/100000000%lx-%lx", a, b);
+		fail("/proc/self/map_files/%lx-100000000%lx", a, b);
+	} else if (sizeof(long) == 8) {
+		fail("/proc/self/map_files/10000000000000000%lx-%lx", a, b);
+		fail("/proc/self/map_files/%lx-10000000000000000%lx", a, b);
+	} else
+		return 1;
+
+	return 0;
+}
new file mode 100644
--- /dev/null
+++ b/tools/testing/selftests/proc/proc-self-map-files-002.c
@@ -0,0 +1,85 @@
+/*
+ * Copyright © 2018 Alexey Dobriyan <adobriyan@gmail.com>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+/* Test readlink /proc/self/map_files/... with address 0. */
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <sys/mman.h>
+#include <stdlib.h>
+
+static void pass(const char *fmt, unsigned long a, unsigned long b)
+{
+	char name[64];
+	char buf[64];
+
+	snprintf(name, sizeof(name), fmt, a, b);
+	if (readlink(name, buf, sizeof(buf)) == -1)
+		exit(1);
+}
+
+static void fail(const char *fmt, unsigned long a, unsigned long b)
+{
+	char name[64];
+	char buf[64];
+
+	snprintf(name, sizeof(name), fmt, a, b);
+	if (readlink(name, buf, sizeof(buf)) == -1 && errno == ENOENT)
+		return;
+	exit(1);
+}
+
+int main(void)
+{
+	const unsigned int PAGE_SIZE = sysconf(_SC_PAGESIZE);
+	void *p;
+	int fd;
+	unsigned long a, b;
+
+	fd = open("/dev/zero", O_RDONLY);
+	if (fd == -1)
+		return 1;
+
+	p = mmap(NULL, PAGE_SIZE, PROT_NONE, MAP_PRIVATE|MAP_FILE|MAP_FIXED, fd, 0);
+	if (p == MAP_FAILED) {
+		if (errno == EPERM)
+			return 2;
+		return 1;
+	}
+
+	a = (unsigned long)p;
+	b = (unsigned long)p + PAGE_SIZE;
+
+	pass("/proc/self/map_files/%lx-%lx", a, b);
+	fail("/proc/self/map_files/ %lx-%lx", a, b);
+	fail("/proc/self/map_files/%lx -%lx", a, b);
+	fail("/proc/self/map_files/%lx- %lx", a, b);
+	fail("/proc/self/map_files/%lx-%lx ", a, b);
+	fail("/proc/self/map_files/0%lx-%lx", a, b);
+	fail("/proc/self/map_files/%lx-0%lx", a, b);
+	if (sizeof(long) == 4) {
+		fail("/proc/self/map_files/100000000%lx-%lx", a, b);
+		fail("/proc/self/map_files/%lx-100000000%lx", a, b);
+	} else if (sizeof(long) == 8) {
+		fail("/proc/self/map_files/10000000000000000%lx-%lx", a, b);
+		fail("/proc/self/map_files/%lx-10000000000000000%lx", a, b);
+	} else
+		return 1;
+
+	return 0;
+}

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH v2] proc: fix /proc/*/map_files lookup some more
  2018-03-03 21:51 [PATCH v2] proc: fix /proc/*/map_files lookup some more Alexey Dobriyan
@ 2018-03-04 20:53 ` Cyrill Gorcunov
  0 siblings, 0 replies; 6+ messages in thread
From: Cyrill Gorcunov @ 2018-03-04 20:53 UTC (permalink / raw)
  To: Alexey Dobriyan; +Cc: akpm, linux-kernel, xemul

On Sun, Mar 04, 2018 at 12:51:30AM +0300, Alexey Dobriyan wrote:
> I totally forgot that _parse_integer() accepts arbitrary amount of
> leading zeroes leading to the following lookups:
> 
> 		OK
> 	# readlink /proc/1/map_files/56427ecba000-56427eddc000
> 	/lib/systemd/systemd
> 
> 		bogus
> 	# readlink /proc/1/map_files/00000000000056427ecba000-56427eddc000
> 	/lib/systemd/systemd
> 	# readlink /proc/1/map_files/56427ecba000-00000000000056427eddc000
> 	/lib/systemd/systemd
> 
> Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Reviewed-by: Cyrill Gorcunov <gorcunov@gmail.com>

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH v2] proc: fix /proc/*/map_files lookup some more
  2018-02-21 20:04     ` Andrew Morton
  2018-02-21 20:29       ` Cyrill Gorcunov
@ 2018-02-21 20:58       ` Alexey Dobriyan
  1 sibling, 0 replies; 6+ messages in thread
From: Alexey Dobriyan @ 2018-02-21 20:58 UTC (permalink / raw)
  To: Andrew Morton; +Cc: linux-kernel, avagin, viro

On Wed, Feb 21, 2018 at 12:04:03PM -0800, Andrew Morton wrote:
> On Wed, 21 Feb 2018 22:53:40 +0300 Alexey Dobriyan <adobriyan@gmail.com> wrote:
> 
> > I totally forgot that _parse_integer() accepts arbitrary amount of
> > leading zeroes leading to the following:
> > 
> > 		OK
> > 	# readlink /proc/1/map_files/56427ecba000-56427eddc000
> > 	/lib/systemd/systemd
> > 
> > 		bogus
> > 	# readlink /proc/1/map_files/00000000000056427ecba000-56427eddc000
> > 	/lib/systemd/systemd
> > 	# readlink /proc/1/map_files/56427ecba000-00000000000056427eddc000
> > 	/lib/systemd/systemd
> > 
> > ...
> > 
> > --- a/fs/proc/base.c
> > +++ b/fs/proc/base.c
> > @@ -1916,6 +1916,8 @@ static int dname_to_vma_addr(struct dentry *dentry,
> >  	unsigned long long sval, eval;
> >  	unsigned int len;
> >  
> > +	if (str[0] == '0' && str[1])
> > +		return -EINVAL;
> >  	len = _parse_integer(str, 16, &sval);
> >  	if (len & KSTRTOX_OVERFLOW)
> >  		return -EINVAL;
> > @@ -1927,6 +1929,8 @@ static int dname_to_vma_addr(struct dentry *dentry,
> >  		return -EINVAL;
> >  	str++;
> >  
> > +	if (str[0] == '0' && str[1])
> > +		return -EINVAL;
> >  	len = _parse_integer(str, 16, &eval);
> >  	if (len & KSTRTOX_OVERFLOW)
> >  		return -EINVAL;
> 
> I don't know this code and I'm all confused.
> 
> - why is the code designed to accept addresses of "0"?

Now I'm confused.
Code rejects, say ,'07ff...-...' because printing with %lx-%lx would never
produce leading zero.

> - how do we know that the first digit of a VMA address will never be 0?

Except when address is exactly 0 but this case is handled by looking at
the second character.

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH v2] proc: fix /proc/*/map_files lookup some more
  2018-02-21 20:04     ` Andrew Morton
@ 2018-02-21 20:29       ` Cyrill Gorcunov
  2018-02-21 20:58       ` Alexey Dobriyan
  1 sibling, 0 replies; 6+ messages in thread
From: Cyrill Gorcunov @ 2018-02-21 20:29 UTC (permalink / raw)
  To: Andrew Morton; +Cc: Alexey Dobriyan, linux-kernel, avagin, viro

On Wed, Feb 21, 2018 at 12:04:03PM -0800, Andrew Morton wrote:
> 
> I don't know this code and I'm all confused.
> 
> - why is the code designed to accept addresses of "0"?

It was never designed to accept addresses of 0, it is rather
a side effect of using sscanf in first place.

The address priting is done via

	len = snprintf(buf, sizeof(buf), "%lx-%lx", p->start, p->end);

> - how do we know that the first digit of a VMA address will never be 0?

It should not be, due to snprintf above.
---

Thanks a lot, Alexey!

Reviewed-by: Cyrill Gorcunov <gorcunov@openvz.org>

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH v2] proc: fix /proc/*/map_files lookup some more
  2018-02-21 19:53   ` [PATCH v2] " Alexey Dobriyan
@ 2018-02-21 20:04     ` Andrew Morton
  2018-02-21 20:29       ` Cyrill Gorcunov
  2018-02-21 20:58       ` Alexey Dobriyan
  0 siblings, 2 replies; 6+ messages in thread
From: Andrew Morton @ 2018-02-21 20:04 UTC (permalink / raw)
  To: Alexey Dobriyan; +Cc: linux-kernel, avagin, viro

On Wed, 21 Feb 2018 22:53:40 +0300 Alexey Dobriyan <adobriyan@gmail.com> wrote:

> I totally forgot that _parse_integer() accepts arbitrary amount of
> leading zeroes leading to the following:
> 
> 		OK
> 	# readlink /proc/1/map_files/56427ecba000-56427eddc000
> 	/lib/systemd/systemd
> 
> 		bogus
> 	# readlink /proc/1/map_files/00000000000056427ecba000-56427eddc000
> 	/lib/systemd/systemd
> 	# readlink /proc/1/map_files/56427ecba000-00000000000056427eddc000
> 	/lib/systemd/systemd
> 
> ...
> 
> --- a/fs/proc/base.c
> +++ b/fs/proc/base.c
> @@ -1916,6 +1916,8 @@ static int dname_to_vma_addr(struct dentry *dentry,
>  	unsigned long long sval, eval;
>  	unsigned int len;
>  
> +	if (str[0] == '0' && str[1])
> +		return -EINVAL;
>  	len = _parse_integer(str, 16, &sval);
>  	if (len & KSTRTOX_OVERFLOW)
>  		return -EINVAL;
> @@ -1927,6 +1929,8 @@ static int dname_to_vma_addr(struct dentry *dentry,
>  		return -EINVAL;
>  	str++;
>  
> +	if (str[0] == '0' && str[1])
> +		return -EINVAL;
>  	len = _parse_integer(str, 16, &eval);
>  	if (len & KSTRTOX_OVERFLOW)
>  		return -EINVAL;

I don't know this code and I'm all confused.

- why is the code designed to accept addresses of "0"?

- how do we know that the first digit of a VMA address will never be 0?

^ permalink raw reply	[flat|nested] 6+ messages in thread

* [PATCH v2] proc: fix /proc/*/map_files lookup some more
  2018-02-21 18:51 ` Al Viro
@ 2018-02-21 19:53   ` Alexey Dobriyan
  2018-02-21 20:04     ` Andrew Morton
  0 siblings, 1 reply; 6+ messages in thread
From: Alexey Dobriyan @ 2018-02-21 19:53 UTC (permalink / raw)
  To: akpm; +Cc: linux-kernel, avagin, viro

I totally forgot that _parse_integer() accepts arbitrary amount of
leading zeroes leading to the following:

		OK
	# readlink /proc/1/map_files/56427ecba000-56427eddc000
	/lib/systemd/systemd

		bogus
	# readlink /proc/1/map_files/00000000000056427ecba000-56427eddc000
	/lib/systemd/systemd
	# readlink /proc/1/map_files/56427ecba000-00000000000056427eddc000
	/lib/systemd/systemd

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
---

 fs/proc/base.c |    4 ++++
 1 file changed, 4 insertions(+)

--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -1916,6 +1916,8 @@ static int dname_to_vma_addr(struct dentry *dentry,
 	unsigned long long sval, eval;
 	unsigned int len;
 
+	if (str[0] == '0' && str[1])
+		return -EINVAL;
 	len = _parse_integer(str, 16, &sval);
 	if (len & KSTRTOX_OVERFLOW)
 		return -EINVAL;
@@ -1927,6 +1929,8 @@ static int dname_to_vma_addr(struct dentry *dentry,
 		return -EINVAL;
 	str++;
 
+	if (str[0] == '0' && str[1])
+		return -EINVAL;
 	len = _parse_integer(str, 16, &eval);
 	if (len & KSTRTOX_OVERFLOW)
 		return -EINVAL;

^ permalink raw reply	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2018-03-04 20:53 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2018-03-03 21:51 [PATCH v2] proc: fix /proc/*/map_files lookup some more Alexey Dobriyan
2018-03-04 20:53 ` Cyrill Gorcunov
  -- strict thread matches above, loose matches on Subject: below --
2018-02-21 18:44 [PATCH] " Alexey Dobriyan
2018-02-21 18:51 ` Al Viro
2018-02-21 19:53   ` [PATCH v2] " Alexey Dobriyan
2018-02-21 20:04     ` Andrew Morton
2018-02-21 20:29       ` Cyrill Gorcunov
2018-02-21 20:58       ` Alexey Dobriyan

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