Revision history [back]
 | 1 | initial version | posted 2020-03-30 10:23:35 +0200  |
Fix a use-after-free vulnerability in the glob function when + expanding ~user in glibc CVE-2020-1752
This Patch fixes it:
diff --git a/posix/glob.c b/posix/glob.c
index e73e35c510..c6cbd0eb43 100644
--- a/posix/glob.c
+++ b/posix/glob.c
@@ -827,31 +827,32 @@ __glob (const char *pattern, int flags, int (*errfunc) (const char *, int),
{
size_t home_len = strlen (p->pw_dir);
size_t rest_len = end_name == NULL ? 0 : strlen (end_name);
- char *d;
+ char *d, *newp;
+ bool use_alloca = glob_use_alloca (alloca_used,
+ home_len + rest_len + 1);
- if (__glibc_unlikely (malloc_dirname))
- free (dirname);
- malloc_dirname = 0;
-
- if (glob_use_alloca (alloca_used, home_len + rest_len + 1))
- dirname = alloca_account (home_len + rest_len + 1,
- alloca_used);
+ if (use_alloca)
+ newp = alloca_account (home_len + rest_len + 1, alloca_used);
else
{
- dirname = malloc (home_len + rest_len + 1);
- if (dirname == NULL)
+ newp = malloc (home_len + rest_len + 1);
+ if (newp == NULL)
{
scratch_buffer_free (&pwtmpbuf);
retval = GLOB_NOSPACE;
goto out;
}
- malloc_dirname = 1;
}
- d = mempcpy (dirname, p->pw_dir, home_len);
+ d = mempcpy (newp, p->pw_dir, home_len);
if (end_name != NULL)
d = mempcpy (d, end_name, rest_len);
*d = '\0';
+ if (__glibc_unlikely (malloc_dirname))
+ free (dirname);
+ dirname = newp;
+ malloc_dirname = !use_alloca;
+
dirlen = home_len + rest_len;
dirname_modified = 1;
}
| | 2 | No.2 Revision |
Fix a use-after-free vulnerability in the glob function when + expanding ~user in glibc CVE-2020-1752
This Patch fixes it:
diff --git a/posix/glob.c b/posix/glob.c
index e73e35c510..c6cbd0eb43 100644
--- a/posix/glob.c
+++ b/posix/glob.c
@@ -827,31 +827,32 @@ __glob (const char *pattern, int flags, int (*errfunc) (const char *, int),
{
size_t home_len = strlen (p->pw_dir);
size_t rest_len = end_name == NULL ? 0 : strlen (end_name);
- char *d;
+ char *d, *newp;
+ bool use_alloca = glob_use_alloca (alloca_used,
+ home_len + rest_len + 1);
- if (__glibc_unlikely (malloc_dirname))
- free (dirname);
- malloc_dirname = 0;
-
- if (glob_use_alloca (alloca_used, home_len + rest_len + 1))
- dirname = alloca_account (home_len + rest_len + 1,
- alloca_used);
+ if (use_alloca)
+ newp = alloca_account (home_len + rest_len + 1, alloca_used);
else
{
- dirname = malloc (home_len + rest_len + 1);
- if (dirname == NULL)
+ newp = malloc (home_len + rest_len + 1);
+ if (newp == NULL)
{
scratch_buffer_free (&pwtmpbuf);
retval = GLOB_NOSPACE;
goto out;
}
- malloc_dirname = 1;
}
- d = mempcpy (dirname, p->pw_dir, home_len);
+ d = mempcpy (newp, p->pw_dir, home_len);
if (end_name != NULL)
d = mempcpy (d, end_name, rest_len);
*d = '\0';
+ if (__glibc_unlikely (malloc_dirname))
+ free (dirname);
+ dirname = newp;
+ malloc_dirname = !use_alloca;
+
dirlen = home_len + rest_len;
dirname_modified = 1;
}
| | 3 | No.3 Revision |
Fix a use-after-free vulnerability in the glob function when expanding ~user in glibc CVE-2020-1752
This Patch fixes it:
diff --git a/posix/glob.c b/posix/glob.c
index e73e35c510..c6cbd0eb43 100644
--- a/posix/glob.c
+++ b/posix/glob.c
@@ -827,31 +827,32 @@ __glob (const char *pattern, int flags, int (*errfunc) (const char *, int),
{
size_t home_len = strlen (p->pw_dir);
size_t rest_len = end_name == NULL ? 0 : strlen (end_name);
- char *d;
+ char *d, *newp;
+ bool use_alloca = glob_use_alloca (alloca_used,
+ home_len + rest_len + 1);
- if (__glibc_unlikely (malloc_dirname))
- free (dirname);
- malloc_dirname = 0;
-
- if (glob_use_alloca (alloca_used, home_len + rest_len + 1))
- dirname = alloca_account (home_len + rest_len + 1,
- alloca_used);
+ if (use_alloca)
+ newp = alloca_account (home_len + rest_len + 1, alloca_used);
else
{
- dirname = malloc (home_len + rest_len + 1);
- if (dirname == NULL)
+ newp = malloc (home_len + rest_len + 1);
+ if (newp == NULL)
{
scratch_buffer_free (&pwtmpbuf);
retval = GLOB_NOSPACE;
goto out;
}
- malloc_dirname = 1;
}
- d = mempcpy (dirname, p->pw_dir, home_len);
+ d = mempcpy (newp, p->pw_dir, home_len);
if (end_name != NULL)
d = mempcpy (d, end_name, rest_len);
*d = '\0';
+ if (__glibc_unlikely (malloc_dirname))
+ free (dirname);
+ dirname = newp;
+ malloc_dirname = !use_alloca;
+
dirlen = home_len + rest_len;
dirname_modified = 1;
}