From 95652cac83605d96cf3849e80e3e3f4dce74f5da Mon Sep 17 00:00:00 2001 From: John Johansen Date: Wed, 6 Sep 2017 16:33:56 -0700 Subject: apparmor: provide a bounded version of label_parse some label/context sources might not be guaranteed to be null terminiated provide a size bounded version of label parse to deal with these. Signed-off-by: John Johansen Acked-by: Seth Arnold --- security/apparmor/include/label.h | 3 +++ security/apparmor/label.c | 35 ++++++++++++++++++++++++----------- 2 files changed, 27 insertions(+), 11 deletions(-) diff --git a/security/apparmor/include/label.h b/security/apparmor/include/label.h index 80e9ba9..d871e7f 100644 --- a/security/apparmor/include/label.h +++ b/security/apparmor/include/label.h @@ -327,6 +327,9 @@ void aa_label_audit(struct audit_buffer *ab, struct aa_label *label, gfp_t gfp); void aa_label_seq_print(struct seq_file *f, struct aa_label *label, gfp_t gfp); void aa_label_printk(struct aa_label *label, gfp_t gfp); +struct aa_label *aa_label_strn_parse(struct aa_label *base, const char *str, + size_t n, gfp_t gfp, bool create, + bool force_stack); struct aa_label *aa_label_parse(struct aa_label *base, const char *str, gfp_t gfp, bool create, bool force_stack); diff --git a/security/apparmor/label.c b/security/apparmor/label.c index 31e2f70..4721338 100644 --- a/security/apparmor/label.c +++ b/security/apparmor/label.c @@ -1808,16 +1808,17 @@ void aa_label_printk(struct aa_label *label, gfp_t gfp) aa_put_ns(ns); } -static int label_count_str_entries(const char *str) +static int label_count_strn_entries(const char *str, size_t n) { + const char *end = str + n; const char *split; int count = 1; AA_BUG(!str); - for (split = aa_label_str_split(str); + for (split = aa_label_strn_split(str, end - str); split; - split = aa_label_str_split(str)) { + split = aa_label_strn_split(str, end - str)) { count++; str = split + 3; } @@ -1845,9 +1846,10 @@ static struct aa_profile *fqlookupn_profile(struct aa_label *base, } /** - * aa_label_parse - parse, validate and convert a text string to a label + * aa_label_strn_parse - parse, validate and convert a text string to a label * @base: base label to use for lookups (NOT NULL) * @str: null terminated text string (NOT NULL) + * @n: length of str to parse, will stop at \0 if encountered before n * @gfp: allocation type * @create: true if should create compound labels if they don't exist * @force_stack: true if should stack even if no leading & @@ -1855,19 +1857,23 @@ static struct aa_profile *fqlookupn_profile(struct aa_label *base, * Returns: the matching refcounted label if present * else ERRPTR */ -struct aa_label *aa_label_parse(struct aa_label *base, const char *str, - gfp_t gfp, bool create, bool force_stack) +struct aa_label *aa_label_strn_parse(struct aa_label *base, const char *str, + size_t n, gfp_t gfp, bool create, + bool force_stack) { DEFINE_VEC(profile, vec); struct aa_label *label, *currbase = base; int i, len, stack = 0, error; + const char *end = str + n; const char *split; AA_BUG(!base); AA_BUG(!str); - str = skip_spaces(str); - len = label_count_str_entries(str); + str = skipn_spaces(str, n); + if (str == NULL) + return ERR_PTR(-EINVAL); + len = label_count_strn_entries(str, end - str); if (*str == '&' || force_stack) { /* stack on top of base */ stack = base->size; @@ -1885,7 +1891,7 @@ struct aa_label *aa_label_parse(struct aa_label *base, const char *str, for (i = 0; i < stack; i++) vec[i] = aa_get_profile(base->vec[i]); - for (split = aa_label_str_split(str), i = stack; + for (split = aa_label_strn_split(str, end - str), i = stack; split && i < len; i++) { vec[i] = fqlookupn_profile(base, currbase, str, split - str); if (!vec[i]) @@ -1897,11 +1903,11 @@ struct aa_label *aa_label_parse(struct aa_label *base, const char *str, if (vec[i]->ns != labels_ns(currbase)) currbase = &vec[i]->label; str = split + 3; - split = aa_label_str_split(str); + split = aa_label_strn_split(str, end - str); } /* last element doesn't have a split */ if (i < len) { - vec[i] = fqlookupn_profile(base, currbase, str, strlen(str)); + vec[i] = fqlookupn_profile(base, currbase, str, end - str); if (!vec[i]) goto fail; } @@ -1933,6 +1939,13 @@ fail: goto out; } +struct aa_label *aa_label_parse(struct aa_label *base, const char *str, + gfp_t gfp, bool create, bool force_stack) +{ + return aa_label_strn_parse(base, str, strlen(str), gfp, create, + force_stack); +} + /** * aa_labelset_destroy - remove all labels from the label set * @ls: label set to cleanup (NOT NULL) -- cgit v1.1