From dbc335d2dc3c437649eb6b39f4e9aee2a13eb0af Mon Sep 17 00:00:00 2001 From: Roberto Sassu Date: Mon, 25 Nov 2013 20:18:52 +0100 Subject: ima: make a copy of template_fmt in template_desc_init_fields() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This patch makes a copy of the 'template_fmt' function argument so that the latter will not be modified by strsep(), which does the splitting by replacing the given separator with '\0'.  IMA: No TPM chip found, activating TPM-bypass!  Unable to handle kernel pointer dereference at virtual kernel address 0000000000842000  Oops: 0004 [#1] SMP  Modules linked in:  CPU: 3 PID: 1 Comm: swapper/0 Not tainted 3.12.0-rc2-00098-g3ce1217d6cd5 #17  task: 000000003ffa0000 ti: 000000003ff84000 task.ti: 000000003ff84000  Krnl PSW : 0704e00180000000 000000000044bf88 (strsep+0x7c/0xa0)             R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:3 CC:2 PM:0 EA:3  Krnl GPRS: 000000000000007c 000000000000007c 000000003ff87d90 0000000000821fd8             0000000000000000 000000000000007c 0000000000aa37e0 0000000000aa9008             0000000000000051 0000000000a114d8 0000000100000002 0000000000842bde             0000000000842bdf 00000000006f97f0 000000000040062c 000000003ff87cf0  Krnl Code: 000000000044bf7c: a7f4000a           brc     15,44bf90             000000000044bf80: b90200cc           ltgr    %r12,%r12            #000000000044bf84: a7840006           brc     8,44bf90            >000000000044bf88: 9200c000           mvi     0(%r12),0             000000000044bf8c: 41c0c001           la      %r12,1(%r12)             000000000044bf90: e3c020000024       stg     %r12,0(%r2)             000000000044bf96: b904002b           lgr     %r2,%r11             000000000044bf9a: ebbcf0700004       lmg     %r11,%r12,112(%r15)  Call Trace:  ([<00000000004005fe>] ima_init_template+0xa2/0x1bc)   [<0000000000a7c896>] ima_init+0x7a/0xa8   [<0000000000a7c938>] init_ima+0x24/0x40   [<00000000001000e8>] do_one_initcall+0x68/0x128   [<0000000000a4eb56>] kernel_init_freeable+0x20a/0x2b4   [<00000000006a1ff4>] kernel_init+0x30/0x178   [<00000000006b69fe>] kernel_thread_starter+0x6/0xc   [<00000000006b69f8>] kernel_thread_starter+0x0/0xc  Last Breaking-Event-Address:   [<000000000044bf42>] strsep+0x36/0xa0 Fixes commit: adf53a7 ima: new templates management mechanism Changelog v1: - make template_fmt 'const char *' (reported-by James Morris) - fix kstrdup memory leak (reported-by James Morris) Reported-by: Heiko Carstens Signed-off-by: Roberto Sassu Signed-off-by: Mimi Zohar Tested-by: Heiko Carstens --- security/integrity/ima/ima_template.c | 21 ++++++++++++++------- 1 file changed, 14 insertions(+), 7 deletions(-) diff --git a/security/integrity/ima/ima_template.c b/security/integrity/ima/ima_template.c index 4e5da990630b..913e1927f916 100644 --- a/security/integrity/ima/ima_template.c +++ b/security/integrity/ima/ima_template.c @@ -90,7 +90,7 @@ static struct ima_template_field *lookup_template_field(const char *field_id) return NULL; } -static int template_fmt_size(char *template_fmt) +static int template_fmt_size(const char *template_fmt) { char c; int template_fmt_len = strlen(template_fmt); @@ -106,23 +106,28 @@ static int template_fmt_size(char *template_fmt) return j + 1; } -static int template_desc_init_fields(char *template_fmt, +static int template_desc_init_fields(const char *template_fmt, struct ima_template_field ***fields, int *num_fields) { - char *c, *template_fmt_ptr = template_fmt; + char *c, *template_fmt_copy; int template_num_fields = template_fmt_size(template_fmt); int i, result = 0; if (template_num_fields > IMA_TEMPLATE_NUM_FIELDS_MAX) return -EINVAL; + /* copying is needed as strsep() modifies the original buffer */ + template_fmt_copy = kstrdup(template_fmt, GFP_KERNEL); + if (template_fmt_copy == NULL) + return -ENOMEM; + *fields = kzalloc(template_num_fields * sizeof(*fields), GFP_KERNEL); if (*fields == NULL) { result = -ENOMEM; goto out; } - for (i = 0; (c = strsep(&template_fmt_ptr, "|")) != NULL && + for (i = 0; (c = strsep(&template_fmt_copy, "|")) != NULL && i < template_num_fields; i++) { struct ima_template_field *f = lookup_template_field(c); @@ -133,10 +138,12 @@ static int template_desc_init_fields(char *template_fmt, (*fields)[i] = f; } *num_fields = i; - return 0; out: - kfree(*fields); - *fields = NULL; + if (result < 0) { + kfree(*fields); + *fields = NULL; + } + kfree(template_fmt_copy); return result; } -- cgit v1.2.3