[packages/libcgroup.git] / libcgroup-0.41-size-of-controller-values.patch

From 5a64a79144e58a62426a34ef51b14e891f042fa2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Nikola=20Forr=C3=B3?= <nforro@redhat.com>
Date: Tue, 17 Apr 2018 13:54:38 +0200
Subject: [PATCH 6/6] Increase maximal size of controller values
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Maximal length of a controller value is determined by CG_VALUE_MAX,
which is equal to 100. That is not sufficient in some cases.

Add new constant CG_CONTROL_VALUE_MAX (to prevent breaking current API)
and set it to 4096, which is usually equal to the amount of bytes that
can be written to a sysctl file directly.

Add warning message about exceeding the limit while parsing
configuration file.

Signed-off-by: Nikola Forró <nforro@redhat.com>
---
 src/api.c                |  6 +++---
 src/libcgroup-internal.h |  5 ++++-
 src/tools/cgset.c        |  4 ++--
 src/wrapper.c            | 17 ++++++++++++-----
 4 files changed, 21 insertions(+), 11 deletions(-)

diff --git a/src/api.c b/src/api.c
index efde2d1..1cd30df 100644
--- a/src/api.c
+++ b/src/api.c
@@ -1561,7 +1561,7 @@ static int cgroup_copy_controller_values(struct cgroup_controller *dst,
 		}
 
 		dst_val = dst->values[i];
-		strncpy(dst_val->value, src_val->value, CG_VALUE_MAX);
+		strncpy(dst_val->value, src_val->value, CG_CONTROL_VALUE_MAX);
 		strncpy(dst_val->name, src_val->name, FILENAME_MAX);
 		dst_val->dirty = src_val->dirty;
 	}
@@ -2286,7 +2286,7 @@ static int cg_rd_ctrl_file(const char *subsys, const char *cgroup,
 	if (ctrl_file < 0)
 		return ECGROUPVALUENOTEXIST;
 
-	*value = calloc(CG_VALUE_MAX, 1);
+	*value = calloc(CG_CONTROL_VALUE_MAX, 1);
 	if (!*value) {
 		close(ctrl_file);
 		last_errno = errno;
@@ -2297,7 +2297,7 @@ static int cg_rd_ctrl_file(const char *subsys, const char *cgroup,
 	 * using %as or fread crashes when we try to read from files like
 	 * memory.stat
 	 */
-	ret = read(ctrl_file, *value, CG_VALUE_MAX-1);
+	ret = read(ctrl_file, *value, CG_CONTROL_VALUE_MAX-1);
 	if (ret < 0) {
 		free(*value);
 		*value = NULL;
diff --git a/src/libcgroup-internal.h b/src/libcgroup-internal.h
index 4c0f46c..3a8e336 100644
--- a/src/libcgroup-internal.h
+++ b/src/libcgroup-internal.h
@@ -32,6 +32,9 @@ __BEGIN_DECLS
 /* Estimated number of groups created */
 #define MAX_GROUP_ELEMENTS	128
 
+/* Maximum length of a value */
+#define CG_CONTROL_VALUE_MAX 4096
+
 #define CG_NV_MAX 100
 #define CG_CONTROLLER_MAX 100
 /* Max number of mounted hierarchies. Event if one controller is mounted per
@@ -73,7 +76,7 @@ __BEGIN_DECLS
 
 struct control_value {
 	char name[FILENAME_MAX];
-	char value[CG_VALUE_MAX];
+	char value[CG_CONTROL_VALUE_MAX];
 	bool dirty;
 };
 
diff --git a/src/tools/cgset.c b/src/tools/cgset.c
index ea9f90d..3d3c8cc 100644
--- a/src/tools/cgset.c
+++ b/src/tools/cgset.c
@@ -151,8 +151,8 @@ int main(int argc, char *argv[])
 				goto err;
 			}
 
-			strncpy(name_value[nv_number].value, buf, CG_VALUE_MAX);
-			name_value[nv_number].value[CG_VALUE_MAX-1] = '\0';
+			strncpy(name_value[nv_number].value, buf, CG_CONTROL_VALUE_MAX);
+			name_value[nv_number].value[CG_CONTROL_VALUE_MAX-1] = '\0';
 
 			nv_number++;
 			break;
diff --git a/src/wrapper.c b/src/wrapper.c
index c03472a..0952823 100644
--- a/src/wrapper.c
+++ b/src/wrapper.c
@@ -132,10 +132,10 @@ int cgroup_add_value_string(struct cgroup_controller *controller,
 	if (!controller)
 		return ECGINVAL;
 
-	if (controller->index >= CG_VALUE_MAX)
+	if (controller->index >= CG_NV_MAX)
 		return ECGMAXVALUESEXCEEDED;
 
-	for (i = 0; i < controller->index && i < CG_VALUE_MAX; i++) {
+	for (i = 0; i < controller->index && i < CG_NV_MAX; i++) {
 		if (!strcmp(controller->values[i]->name, name))
 			return ECGVALUEEXISTS;
 	}
@@ -145,8 +145,15 @@ int cgroup_add_value_string(struct cgroup_controller *controller,
 	if (!cntl_value)
 		return ECGCONTROLLERCREATEFAILED;
 
-	strncpy(cntl_value->name, name, sizeof(cntl_value->name));
-	strncpy(cntl_value->value, value, sizeof(cntl_value->value));
+	if (strlen(value) >= sizeof(cntl_value->value)) {
+		fprintf(stderr, "value exceeds the maximum of %d characters\n",
+			sizeof(cntl_value->value));
+		free(cntl_value);
+		return ECGCONFIGPARSEFAIL;
+	}
+
+	strncpy(cntl_value->name, name, sizeof(cntl_value->name) - 1);
+	strncpy(cntl_value->value, value, sizeof(cntl_value->value) - 1);
 	cntl_value->dirty = true;
 	controller->values[controller->index] = cntl_value;
 	controller->index++;
@@ -356,7 +363,7 @@ int cgroup_set_value_string(struct cgroup_controller *controller,
 	for (i = 0; i < controller->index; i++) {
 		struct control_value *val = controller->values[i];
 		if (!strcmp(val->name, name)) {
-			strncpy(val->value, value, CG_VALUE_MAX);
+			strncpy(val->value, value, CG_CONTROL_VALUE_MAX - 1);
 			val->dirty = true;
 			return 0;
 		}
-- 
2.17.0
Commit	Line	Data
9665627f AM	1	From 5a64a79144e58a62426a34ef51b14e891f042fa2 Mon Sep 17 00:00:00 2001
	2	From: =?UTF-8?q?Nikola=20Forr=C3=B3?= <nforro@redhat.com>
	3	Date: Tue, 17 Apr 2018 13:54:38 +0200
	4	Subject: [PATCH 6/6] Increase maximal size of controller values
	5	MIME-Version: 1.0
	6	Content-Type: text/plain; charset=UTF-8
	7	Content-Transfer-Encoding: 8bit
	8
	9	Maximal length of a controller value is determined by CG_VALUE_MAX,
	10	which is equal to 100. That is not sufficient in some cases.
	11
	12	Add new constant CG_CONTROL_VALUE_MAX (to prevent breaking current API)
	13	and set it to 4096, which is usually equal to the amount of bytes that
	14	can be written to a sysctl file directly.
	15
	16	Add warning message about exceeding the limit while parsing
	17	configuration file.
	18
	19	Signed-off-by: Nikola Forró <nforro@redhat.com>
	20	---
	21	src/api.c \| 6 +++---
	22	src/libcgroup-internal.h \| 5 ++++-
	23	src/tools/cgset.c \| 4 ++--
	24	src/wrapper.c \| 17 ++++++++++++-----
	25	4 files changed, 21 insertions(+), 11 deletions(-)
	26
	27	diff --git a/src/api.c b/src/api.c
	28	index efde2d1..1cd30df 100644
	29	--- a/src/api.c
	30	+++ b/src/api.c
	31	@@ -1561,7 +1561,7 @@ static int cgroup_copy_controller_values(struct cgroup_controller *dst,
	32	}
	33
	34	dst_val = dst->values[i];
	35	- strncpy(dst_val->value, src_val->value, CG_VALUE_MAX);
	36	+ strncpy(dst_val->value, src_val->value, CG_CONTROL_VALUE_MAX);
	37	strncpy(dst_val->name, src_val->name, FILENAME_MAX);
	38	dst_val->dirty = src_val->dirty;
	39	}
	40	@@ -2286,7 +2286,7 @@ static int cg_rd_ctrl_file(const char subsys, const char cgroup,
	41	if (ctrl_file < 0)
	42	return ECGROUPVALUENOTEXIST;
	43
	44	- *value = calloc(CG_VALUE_MAX, 1);
	45	+ *value = calloc(CG_CONTROL_VALUE_MAX, 1);
	46	if (!*value) {
	47	close(ctrl_file);
	48	last_errno = errno;
	49	@@ -2297,7 +2297,7 @@ static int cg_rd_ctrl_file(const char subsys, const char cgroup,
	50	* using %as or fread crashes when we try to read from files like
	51	* memory.stat
	52	*/
	53	- ret = read(ctrl_file, *value, CG_VALUE_MAX-1);
	54	+ ret = read(ctrl_file, *value, CG_CONTROL_VALUE_MAX-1);
	55	if (ret < 0) {
	56	free(*value);
	57	*value = NULL;
	58	diff --git a/src/libcgroup-internal.h b/src/libcgroup-internal.h
	59	index 4c0f46c..3a8e336 100644
	60	--- a/src/libcgroup-internal.h
	61	+++ b/src/libcgroup-internal.h
	62	@@ -32,6 +32,9 @@ __BEGIN_DECLS
	63	/* Estimated number of groups created */
	64	#define MAX_GROUP_ELEMENTS 128
65
66	+/* Maximum length of a value */
67	+#define CG_CONTROL_VALUE_MAX 4096
68	+
69	#define CG_NV_MAX 100
70	#define CG_CONTROLLER_MAX 100
71	/* Max number of mounted hierarchies. Event if one controller is mounted per
72	@@ -73,7 +76,7 @@ __BEGIN_DECLS
73
74	struct control_value {
75	char name[FILENAME_MAX];
76	- char value[CG_VALUE_MAX];
77	+ char value[CG_CONTROL_VALUE_MAX];
78	bool dirty;
79	};
80
81	diff --git a/src/tools/cgset.c b/src/tools/cgset.c
82	index ea9f90d..3d3c8cc 100644
83	--- a/src/tools/cgset.c
84	+++ b/src/tools/cgset.c
85	@@ -151,8 +151,8 @@ int main(int argc, char *argv[])
86	goto err;
87	}
88
89	- strncpy(name_value[nv_number].value, buf, CG_VALUE_MAX);
90	- name_value[nv_number].value[CG_VALUE_MAX-1] = '\0';
91	+ strncpy(name_value[nv_number].value, buf, CG_CONTROL_VALUE_MAX);
92	+ name_value[nv_number].value[CG_CONTROL_VALUE_MAX-1] = '\0';
93
94	nv_number++;
95	break;
96	diff --git a/src/wrapper.c b/src/wrapper.c
97	index c03472a..0952823 100644
98	--- a/src/wrapper.c
99	+++ b/src/wrapper.c
100	@@ -132,10 +132,10 @@ int cgroup_add_value_string(struct cgroup_controller *controller,
101	if (!controller)
102	return ECGINVAL;
103
104	- if (controller->index >= CG_VALUE_MAX)
105	+ if (controller->index >= CG_NV_MAX)
106	return ECGMAXVALUESEXCEEDED;
107
108	- for (i = 0; i < controller->index && i < CG_VALUE_MAX; i++) {
109	+ for (i = 0; i < controller->index && i < CG_NV_MAX; i++) {
110	if (!strcmp(controller->values[i]->name, name))
111	return ECGVALUEEXISTS;
112	}
113	@@ -145,8 +145,15 @@ int cgroup_add_value_string(struct cgroup_controller *controller,
114	if (!cntl_value)
115	return ECGCONTROLLERCREATEFAILED;
116
117	- strncpy(cntl_value->name, name, sizeof(cntl_value->name));
118	- strncpy(cntl_value->value, value, sizeof(cntl_value->value));
119	+ if (strlen(value) >= sizeof(cntl_value->value)) {
120	+ fprintf(stderr, "value exceeds the maximum of %d characters\n",
121	+ sizeof(cntl_value->value));
122	+ free(cntl_value);
123	+ return ECGCONFIGPARSEFAIL;
124	+ }
125	+
126	+ strncpy(cntl_value->name, name, sizeof(cntl_value->name) - 1);
127	+ strncpy(cntl_value->value, value, sizeof(cntl_value->value) - 1);
128	cntl_value->dirty = true;
129	controller->values[controller->index] = cntl_value;
130	controller->index++;
131	@@ -356,7 +363,7 @@ int cgroup_set_value_string(struct cgroup_controller *controller,
132	for (i = 0; i < controller->index; i++) {
133	struct control_value *val = controller->values[i];
134	if (!strcmp(val->name, name)) {
135	- strncpy(val->value, value, CG_VALUE_MAX);
136	+ strncpy(val->value, value, CG_CONTROL_VALUE_MAX - 1);
137	val->dirty = true;
138	return 0;
139	}
140	--
141	2.17.0
142