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Make path_concat return empty string on ENOBUFS

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Stephen Gallagher 2012-03-16 08:32:11 -04:00
parent 82d0379be9
commit 4e0c978e54
2 changed files with 159 additions and 1 deletions
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153
0003-path_utils-path_concat-should-return-empty-string-on.patch Normal file
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@ -0,0 +1,153 @@
From c4fdad249bf62d61856d26f97849e61351a356d5 Mon Sep 17 00:00:00 2001
From: Stephen Gallagher <sgallagh@redhat.com>
Date: Wed, 7 Mar 2012 09:29:46 -0500
Subject: [PATCH] path_utils: path_concat should return empty string on
ENOBUFS
Also clean up the code a bit and add more comments
---
path_utils/path_utils.c | 48 ++++++++++++++++++++++++++++++++++---------
path_utils/path_utils.h | 3 +-
path_utils/path_utils_ut.c | 19 +++++++++++++---
3 files changed, 55 insertions(+), 15 deletions(-)
diff --git a/path_utils/path_utils.c b/path_utils/path_utils.c
index 25ca4267fc0d7d9f3483646c2aef22fcdef1eb24..0a758c5bfd09ef5708e9f68d3aecc0733607e3d8 100644
--- a/path_utils/path_utils.c
+++ b/path_utils/path_utils.c
@@ -192,6 +192,7 @@ bool is_absolute_path(const char *path)
int path_concat(char *path, size_t path_size, const char *head, const char *tail)
{
+ int ret;
const char *p, *src;
char *dst, *dst_end;
@@ -201,13 +202,27 @@ int path_concat(char *path, size_t path_size, const char *head, const char *tail
dst_end = path + path_size - 1; /* -1 allows for NULL terminator */
if (head && *head) {
- for (p = head; *p; p++); /* walk to end of head */
- for (p--; p > head && *p == '/'; p--); /* skip any trailing slashes in head */
- if ((p - head) > path_size-1) return ENOBUFS;
- for (src = head; src <= p && dst < dst_end;) *dst++ = *src++; /* copy head */
+ /* walk to end of head */
+ for (p = head; *p; p++);
+
+ /* skip any trailing slashes in head */
+ for (p--; p > head && *p == '/'; p--);
+
+ /* If the length of head exceeds the buffer size, fail */
+ if ((p - head) > path_size-1) {
+ ret = ENOBUFS;
+ goto fail;
+ }
+
+ /* Copy head into path */
+ for (src = head; src <= p && dst < dst_end;) {
+ *dst++ = *src++;
+ }
}
if (tail && *tail) {
- for (p = tail; *p && *p == '/'; p++); /* skip any leading slashes in tail */
+ /* skip any leading slashes in tail */
+ for (p = tail; *p && *p == '/'; p++);
+
if (dst > path)
/* insert single slash between head & tail
* Making sure not to add an extra if the
@@ -218,15 +233,28 @@ int path_concat(char *path, size_t path_size, const char *head, const char *tail
if (dst < dst_end && *(dst-1) != '/') {
*dst++ = '/';
}
- for (src = p; *src && dst < dst_end;) *dst++ = *src++; /* copy tail */
- if (*src) return ENOBUFS; /* failed to copy everything */
+
+ /* Copy the tail into the path */
+ for (src = p; *src && dst < dst_end;) {
+ *dst++ = *src++;
+ }
+
+ /* If we got past dst_end and there is more data
+ * in the src buffer, we should return ENOBUFS
+ */
+ if (*src) {
+ ret = ENOBUFS; /* failed to copy everything */
+ goto fail;
+ }
}
*dst = 0;
- if (dst > dst_end) {
- return ENOBUFS;
- }
+
return SUCCESS;
+fail:
+ /* On failure, set the buffer to the empty string for safety */
+ *path = '\0';
+ return ret;
}
int make_path_absolute(char *absolute_path, size_t absolute_path_size, const char *path)
diff --git a/path_utils/path_utils.h b/path_utils/path_utils.h
index 2fd567c4eaa30ee1eb05af868d7d14b6e2a71a43..17ed1f4324a192c32d8229417d527424ef01ccd2 100644
--- a/path_utils/path_utils.h
+++ b/path_utils/path_utils.h
@@ -198,7 +198,8 @@ bool is_absolute_path(const char *path);
* @param[in] tail The second component of the path
*
* @return \c SUCCESS if successful, non-zero error code otherwise.
- * \li \c ENOBUFS If the buffer space is too small
+ * \li \c ENOBUFS If the buffer space is too small. In this case,
+ * path will be set to an empty string.
*/
int path_concat(char *path, size_t path_size, const char *head, const char *tail);
diff --git a/path_utils/path_utils_ut.c b/path_utils/path_utils_ut.c
index 34462cfdd4a2238f878a170fba2481b31f96e33e..aadd89b74420a4f8bc51ace779ecfb4223afa0e3 100644
--- a/path_utils/path_utils_ut.c
+++ b/path_utils/path_utils_ut.c
@@ -252,24 +252,35 @@ START_TEST(test_path_concat_neg)
char small[3];
char small2[5];
char small3[7];
- char p2[9];
+ char p2[10];
/* these two test different conditions */
/* Test if head is longer than the buffer */
fail_unless(path_concat(small, 3, "/foo", "bar") == ENOBUFS);
+ /* On ENOBUFS, path should be empty */
+ fail_unless_str_equal(small, "");
/* Test if head is the same length as the buffer */
fail_unless(path_concat(small2, 5, "/foo", "bar") == ENOBUFS);
+ /* On ENOBUFS, path should be empty */
+ fail_unless_str_equal(small2, "");
/* Test if head+tail is the longer than the buffer */
fail_unless(path_concat(small3, 7, "/foo", "bar") == ENOBUFS);
+ /* On ENOBUFS, path should be empty */
+ fail_unless_str_equal(small3, "");
/* off-by-one */
- p2[8] = 1; /* Check whether we've written too far */
+ /* Fill with garbage data for now */
+ memset(p2, 'Z', 9);
+ p2[9] = '\0';
+
fail_unless(path_concat(p2, 8, "/foo", "bar") == ENOBUFS);
- fail_unless(p2[8] == 1); /* This should be untouched */
- fail_unless_str_equal(p2, "/foo/ba");
+ /* Make sure we don't write past the end of the buffer */
+ fail_unless(p2[8] == 'Z', "Got [%d]", p2[8]);
+ /* On ENOBUFS, path should be empty */
+ fail_unless_str_equal(p2, "");
}
END_TEST
--
1.7.7.6

7
ding-libs.spec
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@ -1,6 +1,6 @@
Name: ding-libs
Version: 0.1.3
Release: 7%{?dist}
Release: 8%{?dist}
Summary: "Ding is not GLib" assorted utility libraries
Group: Development/Libraries
License: LGPLv3+
@ -18,6 +18,7 @@ BuildRoot: %(mktemp -ud %{_tmppath}/%{name}-%{version}-%{release}-XXXXXX)
Patch0001: 0001-path_utils-handle-off-by-one-error-in-path_concat.patch
Patch0002: 0002-path_utils-Handle-in-path_concat.patch
Patch0003: 0003-path_utils-path_concat-should-return-empty-string-on.patch
### Dependencies ###
@ -252,6 +253,7 @@ structure
%patch0001 -p1
%patch0002 -p1
%patch0003 -p1
%build
%configure \
@ -285,6 +287,9 @@ rm -f */doc/html/installdox
rm -rf $RPM_BUILD_ROOT
%changelog
* Tue Mar 06 2012 Stephen Gallagher <sgallagh@redhat.com> - 0.1.3-8
- Make path_concat return empty string on ENOBUFS
* Tue Mar 06 2012 Stephen Gallagher <sgallagh@redhat.com> - 0.1.3-7
- Fix off-by-one bug in path_concat()
- Resolves: rhbz#799347 - path_utils:test_path_concat_neg fails on 64-bit big