diff options
| author | Kohei Kaigai <Kohei.Kaigai@emea.nec.com> | 2011-05-26 14:59:25 -0400 |
|---|---|---|
| committer | Eric Paris <eparis@redhat.com> | 2011-05-26 17:20:53 -0400 |
| commit | 0f7e4c33eb2c40b1e9cc24d2eab6de5921bc619c (patch) | |
| tree | 793c5f834751215dfc93b05540fa9ed46c64ee07 /security | |
| parent | ea77f7a2e8561012cf100c530170f12351c3b53e (diff) | |
selinux: fix case of names with whitespace/multibytes on /selinux/create
I submit the patch again, according to patch submission convension.
This patch enables to accept percent-encoded object names as forth
argument of /selinux/create interface to avoid possible bugs when we
give an object name including whitespace or multibutes.
E.g) if and when a userspace object manager tries to create a new object
named as "resolve.conf but fake", it shall give this name as the forth
argument of the /selinux/create. But sscanf() logic in kernel space
fetches only the part earlier than the first whitespace.
In this case, selinux may unexpectedly answer a default security context
configured to "resolve.conf", but it is bug.
Although I could not test this patch on named TYPE_TRANSITION rules
actually, But debug printk() message seems to me the logic works
correctly.
I assume the libselinux provides an interface to apply this logic
transparently, so nothing shall not be changed from the viewpoint of
application.
Signed-off-by: KaiGai Kohei <kohei.kaigai@emea.nec.com>
Signed-off-by: Eric Paris <eparis@redhat.com>
Diffstat (limited to 'security')
| -rw-r--r-- | security/selinux/selinuxfs.c | 37 |
1 files changed, 36 insertions, 1 deletions
diff --git a/security/selinux/selinuxfs.c b/security/selinux/selinuxfs.c index fde4e9d64bfd..19489042fdf7 100644 --- a/security/selinux/selinuxfs.c +++ b/security/selinux/selinuxfs.c @@ -29,6 +29,7 @@ #include <linux/audit.h> #include <linux/uaccess.h> #include <linux/kobject.h> +#include <linux/ctype.h> /* selinuxfs pseudo filesystem for exporting the security policy API. Based on the proc code and the fs/nfsd/nfsctl.c code. */ @@ -751,6 +752,14 @@ out: return length; } +static inline int hexcode_to_int(int code) { + if (code == '\0' || !isxdigit(code)) + return -1; + if (isdigit(code)) + return code - '0'; + return tolower(code) - 'a' + 10; +} + static ssize_t sel_write_create(struct file *file, char *buf, size_t size) { char *scon = NULL, *tcon = NULL; @@ -785,8 +794,34 @@ static ssize_t sel_write_create(struct file *file, char *buf, size_t size) nargs = sscanf(buf, "%s %s %hu %s", scon, tcon, &tclass, namebuf); if (nargs < 3 || nargs > 4) goto out; - if (nargs == 4) + if (nargs == 4) { + /* + * If and when the name of new object to be queried contains + * either whitespace or multibyte characters, they shall be + * encoded based on the percentage-encoding rule. + * If not encoded, the sscanf logic picks up only left-half + * of the supplied name; splitted by a whitespace unexpectedly. + */ + char *r, *w; + int c1, c2; + + r = w = namebuf; + do { + c1 = *r++; + if (c1 == '+') + c1 = ' '; + else if (c1 == '%') { + if ((c1 = hexcode_to_int(*r++)) < 0) + goto out; + if ((c2 = hexcode_to_int(*r++)) < 0) + goto out; + c1 = (c1 << 4) | c2; + } + *w++ = c1; + } while (c1 != '\0'); + objname = namebuf; + } length = security_context_to_sid(scon, strlen(scon) + 1, &ssid); if (length) |