* [PATCH v2 1/2] libselinux: ensure strlen() is not called on NULL
@ 2019-09-20 5:59 Nicolas Iooss
2019-09-20 5:59 ` [PATCH v2 2/2] libselinux: do not add rc to pos twice Nicolas Iooss
2019-09-20 14:22 ` [PATCH v2 1/2] libselinux: ensure strlen() is not called on NULL Stephen Smalley
0 siblings, 2 replies; 5+ messages in thread
From: Nicolas Iooss @ 2019-09-20 5:59 UTC (permalink / raw)
To: selinux
When compile_regex() calls regex_prepare_data() and this function fails
in the following condition:
*regex = regex_data_create();
if (!(*regex))
return -1;
... error_data has been zero-ed and compile_regex() calls:
regex_format_error(&error_data,
regex_error_format_buffer,
sizeof(regex_error_format_buffer));
This leads to a call to strlen(error_data->error_buffer), where
error_data->error_buffer is NULL.
Avoid this by checking that error_data->error_buffer is not NULL before
trying to format it.
This issue has been found using clang's static analyzer:
https://337-118970575-gh.circle-artifacts.com/0/output-scan-build/2019-09-01-181851-6152-1/report-0b122b.html#EndPath
Signed-off-by: Nicolas Iooss <nicolas.iooss@m4x.org>
---
libselinux/src/regex.c | 23 +++++++++++++++++++++++
1 file changed, 23 insertions(+)
diff --git a/libselinux/src/regex.c b/libselinux/src/regex.c
index a6fcbbfec1f3..c835dd1b0e5d 100644
--- a/libselinux/src/regex.c
+++ b/libselinux/src/regex.c
@@ -519,6 +519,29 @@ void regex_format_error(struct regex_error_data const *error_data, char *buffer,
if (pos >= buf_size)
goto truncated;
+ /* Return early if there is no error to format */
+#ifdef USE_PCRE2
+ if (!error_data->error_code) {
+ rc = snprintf(buffer + pos, buf_size - pos, "no error code");
+ if (rc < 0)
+ abort();
+ pos += rc;
+ if (pos >= buf_size)
+ goto truncated;
+ return;
+ }
+#else
+ if (!error_data->error_buffer) {
+ rc = snprintf(buffer + pos, buf_size - pos, "empty error");
+ if (rc < 0)
+ abort();
+ pos += rc;
+ if (pos >= buf_size)
+ goto truncated;
+ return;
+ }
+#endif
+
if (error_data->error_offset > 0) {
#ifdef USE_PCRE2
rc = snprintf(buffer + pos, buf_size - pos, "At offset %zu: ",
--
2.22.0
^ permalink raw reply related [flat|nested] 5+ messages in thread* [PATCH v2 2/2] libselinux: do not add rc to pos twice
2019-09-20 5:59 [PATCH v2 1/2] libselinux: ensure strlen() is not called on NULL Nicolas Iooss
@ 2019-09-20 5:59 ` Nicolas Iooss
2019-09-20 14:22 ` Stephen Smalley
2019-09-23 13:54 ` Stephen Smalley
2019-09-20 14:22 ` [PATCH v2 1/2] libselinux: ensure strlen() is not called on NULL Stephen Smalley
1 sibling, 2 replies; 5+ messages in thread
From: Nicolas Iooss @ 2019-09-20 5:59 UTC (permalink / raw)
To: selinux
In regex_format_error(), when error_data->error_offset is zero, rc is
not updated and should not be added to pos again.
Signed-off-by: Nicolas Iooss <nicolas.iooss@m4x.org>
---
libselinux/src/regex.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/libselinux/src/regex.c b/libselinux/src/regex.c
index c835dd1b0e5d..770bc3ea1310 100644
--- a/libselinux/src/regex.c
+++ b/libselinux/src/regex.c
@@ -552,10 +552,10 @@ void regex_format_error(struct regex_error_data const *error_data, char *buffer,
#endif
if (rc < 0)
abort();
+ pos += rc;
+ if (pos >= buf_size)
+ goto truncated;
}
- pos += rc;
- if (pos >= buf_size)
- goto truncated;
#ifdef USE_PCRE2
rc = pcre2_get_error_message(error_data->error_code,
--
2.22.0
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH v2 2/2] libselinux: do not add rc to pos twice
2019-09-20 5:59 ` [PATCH v2 2/2] libselinux: do not add rc to pos twice Nicolas Iooss
@ 2019-09-20 14:22 ` Stephen Smalley
2019-09-23 13:54 ` Stephen Smalley
1 sibling, 0 replies; 5+ messages in thread
From: Stephen Smalley @ 2019-09-20 14:22 UTC (permalink / raw)
To: Nicolas Iooss, selinux
On 9/20/19 1:59 AM, Nicolas Iooss wrote:
> In regex_format_error(), when error_data->error_offset is zero, rc is
> not updated and should not be added to pos again.
>
> Signed-off-by: Nicolas Iooss <nicolas.iooss@m4x.org>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
> ---
> libselinux/src/regex.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/libselinux/src/regex.c b/libselinux/src/regex.c
> index c835dd1b0e5d..770bc3ea1310 100644
> --- a/libselinux/src/regex.c
> +++ b/libselinux/src/regex.c
> @@ -552,10 +552,10 @@ void regex_format_error(struct regex_error_data const *error_data, char *buffer,
> #endif
> if (rc < 0)
> abort();
> + pos += rc;
> + if (pos >= buf_size)
> + goto truncated;
> }
> - pos += rc;
> - if (pos >= buf_size)
> - goto truncated;
>
> #ifdef USE_PCRE2
> rc = pcre2_get_error_message(error_data->error_code,
>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v2 2/2] libselinux: do not add rc to pos twice
2019-09-20 5:59 ` [PATCH v2 2/2] libselinux: do not add rc to pos twice Nicolas Iooss
2019-09-20 14:22 ` Stephen Smalley
@ 2019-09-23 13:54 ` Stephen Smalley
1 sibling, 0 replies; 5+ messages in thread
From: Stephen Smalley @ 2019-09-23 13:54 UTC (permalink / raw)
To: Nicolas Iooss, selinux
On 9/20/19 1:59 AM, Nicolas Iooss wrote:
> In regex_format_error(), when error_data->error_offset is zero, rc is
> not updated and should not be added to pos again.
Thanks, both patches applied.
>
> Signed-off-by: Nicolas Iooss <nicolas.iooss@m4x.org>
> ---
> libselinux/src/regex.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/libselinux/src/regex.c b/libselinux/src/regex.c
> index c835dd1b0e5d..770bc3ea1310 100644
> --- a/libselinux/src/regex.c
> +++ b/libselinux/src/regex.c
> @@ -552,10 +552,10 @@ void regex_format_error(struct regex_error_data const *error_data, char *buffer,
> #endif
> if (rc < 0)
> abort();
> + pos += rc;
> + if (pos >= buf_size)
> + goto truncated;
> }
> - pos += rc;
> - if (pos >= buf_size)
> - goto truncated;
>
> #ifdef USE_PCRE2
> rc = pcre2_get_error_message(error_data->error_code,
>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v2 1/2] libselinux: ensure strlen() is not called on NULL
2019-09-20 5:59 [PATCH v2 1/2] libselinux: ensure strlen() is not called on NULL Nicolas Iooss
2019-09-20 5:59 ` [PATCH v2 2/2] libselinux: do not add rc to pos twice Nicolas Iooss
@ 2019-09-20 14:22 ` Stephen Smalley
1 sibling, 0 replies; 5+ messages in thread
From: Stephen Smalley @ 2019-09-20 14:22 UTC (permalink / raw)
To: Nicolas Iooss, selinux
On 9/20/19 1:59 AM, Nicolas Iooss wrote:
> When compile_regex() calls regex_prepare_data() and this function fails
> in the following condition:
>
> *regex = regex_data_create();
> if (!(*regex))
> return -1;
>
> ... error_data has been zero-ed and compile_regex() calls:
>
> regex_format_error(&error_data,
> regex_error_format_buffer,
> sizeof(regex_error_format_buffer));
>
> This leads to a call to strlen(error_data->error_buffer), where
> error_data->error_buffer is NULL.
>
> Avoid this by checking that error_data->error_buffer is not NULL before
> trying to format it.
>
> This issue has been found using clang's static analyzer:
> https://337-118970575-gh.circle-artifacts.com/0/output-scan-build/2019-09-01-181851-6152-1/report-0b122b.html#EndPath
>
> Signed-off-by: Nicolas Iooss <nicolas.iooss@m4x.org>
Personally, I would have just used a single error message for both cases
(and only wrapped the condition itself with #ifdef...#else...#endif),
but I'm ok with this as well.
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
> ---
> libselinux/src/regex.c | 23 +++++++++++++++++++++++
> 1 file changed, 23 insertions(+)
>
> diff --git a/libselinux/src/regex.c b/libselinux/src/regex.c
> index a6fcbbfec1f3..c835dd1b0e5d 100644
> --- a/libselinux/src/regex.c
> +++ b/libselinux/src/regex.c
> @@ -519,6 +519,29 @@ void regex_format_error(struct regex_error_data const *error_data, char *buffer,
> if (pos >= buf_size)
> goto truncated;
>
> + /* Return early if there is no error to format */
> +#ifdef USE_PCRE2
> + if (!error_data->error_code) {
> + rc = snprintf(buffer + pos, buf_size - pos, "no error code");
> + if (rc < 0)
> + abort();
> + pos += rc;
> + if (pos >= buf_size)
> + goto truncated;
> + return;
> + }
> +#else
> + if (!error_data->error_buffer) {
> + rc = snprintf(buffer + pos, buf_size - pos, "empty error");
> + if (rc < 0)
> + abort();
> + pos += rc;
> + if (pos >= buf_size)
> + goto truncated;
> + return;
> + }
> +#endif
> +
> if (error_data->error_offset > 0) {
> #ifdef USE_PCRE2
> rc = snprintf(buffer + pos, buf_size - pos, "At offset %zu: ",
>
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2019-09-23 13:54 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
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2019-09-20 5:59 [PATCH v2 1/2] libselinux: ensure strlen() is not called on NULL Nicolas Iooss
2019-09-20 5:59 ` [PATCH v2 2/2] libselinux: do not add rc to pos twice Nicolas Iooss
2019-09-20 14:22 ` Stephen Smalley
2019-09-23 13:54 ` Stephen Smalley
2019-09-20 14:22 ` [PATCH v2 1/2] libselinux: ensure strlen() is not called on NULL Stephen Smalley
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