mkfs: terminate getsubopt arrays properly

Having not drank any (or maybe too much) coffee this morning, I typed:

$ mkfs.xfs -d agcount=3 -d nrext64=0
Segmentation fault

I traced this down to getsubopt walking off the end of the dopts.subopts
array.  The manpage says you're supposed to terminate the suboptions
string array with a NULL entry, but the structure definition uses
MAX_SUBOPTS/D_MAX_OPTS directly, which means there is no terminator.

Explicitly terminate each suboption array with a NULL entry after
making room for it.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
[sandeen: explicitly add NULL terminators & clarify comment]
Reviewed-by: Eric Sandeen <sandeen@sandeen.net>
Signed-off-by: Eric Sandeen <sandeen@sandeen.net>

diff --git a/mkfs/xfs_mkfs.c b/mkfs/xfs_mkfs.c
index db322b3aa335971c6379fe2127803a4be11d6383..b140b8153530c239fc21ca8ee925fde687c32c86 100644 (file)
--- a/mkfs/xfs_mkfs.c
+++ b/mkfs/xfs_mkfs.c
@@ -140,8 +140,11 @@ enum {
        M_MAX_OPTS,
 };
 
-/* Just define the max options array size manually right now */
-#define MAX_SUBOPTS    D_MAX_OPTS
+/*
+ * Just define the max options array size manually to the largest
+ * enum right now, leaving room for a NULL terminator at the end
+ */
+#define MAX_SUBOPTS    (D_MAX_OPTS + 1)
 
 #define SUBOPT_NEEDS_VAL       (-1LL)
 #define MAX_CONFLICTS  8
@@ -251,6 +254,7 @@ static struct opt_params bopts = {
        .ini_section = "block",
        .subopts = {
                [B_SIZE] = "size",
+               [B_MAX_OPTS] = NULL,
        },
        .subopt_params = {
                { .index = B_SIZE,
@@ -277,6 +281,7 @@ static struct opt_params copts = {
        .name = 'c',
        .subopts = {
                [C_OPTFILE] = "options",
+               [C_MAX_OPTS] = NULL,
        },
        .subopt_params = {
                { .index = C_OPTFILE,
@@ -306,6 +311,7 @@ static struct opt_params dopts = {
                [D_EXTSZINHERIT] = "extszinherit",
                [D_COWEXTSIZE] = "cowextsize",
                [D_DAXINHERIT] = "daxinherit",
+               [D_MAX_OPTS] = NULL,
        },
        .subopt_params = {
                { .index = D_AGCOUNT,
@@ -443,6 +449,7 @@ static struct opt_params iopts = {
                [I_PROJID32BIT] = "projid32bit",
                [I_SPINODES] = "sparse",
                [I_NREXT64] = "nrext64",
+               [I_MAX_OPTS] = NULL,
        },
        .subopt_params = {
                { .index = I_ALIGN,
@@ -515,6 +522,7 @@ static struct opt_params lopts = {
                [L_FILE] = "file",
                [L_NAME] = "name",
                [L_LAZYSBCNTR] = "lazy-count",
+               [L_MAX_OPTS] = NULL,
        },
        .subopt_params = {
                { .index = L_AGNUM,
@@ -607,6 +615,7 @@ static struct opt_params nopts = {
                [N_SIZE] = "size",
                [N_VERSION] = "version",
                [N_FTYPE] = "ftype",
+               [N_MAX_OPTS] = NULL,
        },
        .subopt_params = {
                { .index = N_SIZE,
@@ -642,6 +651,7 @@ static struct opt_params ropts = {
                [R_FILE] = "file",
                [R_NAME] = "name",
                [R_NOALIGN] = "noalign",
+               [R_MAX_OPTS] = NULL,
        },
        .subopt_params = {
                { .index = R_EXTSIZE,
@@ -689,6 +699,7 @@ static struct opt_params sopts = {
        .subopts = {
                [S_SIZE] = "size",
                [S_SECTSIZE] = "sectsize",
+               [S_MAX_OPTS] = NULL,
        },
        .subopt_params = {
                { .index = S_SIZE,
@@ -725,6 +736,7 @@ static struct opt_params mopts = {
                [M_REFLINK] = "reflink",
                [M_INOBTCNT] = "inobtcount",
                [M_BIGTIME] = "bigtime",
+               [M_MAX_OPTS] = NULL,
        },
        .subopt_params = {
                { .index = M_CRC,