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[PATCH 06/15] mkfs: validate logarithmic parameters sanely

To: xfs@xxxxxxxxxxx
Subject: [PATCH 06/15] mkfs: validate logarithmic parameters sanely
From: Dave Chinner <david@xxxxxxxxxxxxx>
Date: Fri, 29 Nov 2013 12:43:41 +1100
Delivered-to: xfs@xxxxxxxxxxx
In-reply-to: <1385689430-10103-1-git-send-email-david@xxxxxxxxxxxxx>
References: <1385689430-10103-1-git-send-email-david@xxxxxxxxxxxxx>
From: Dave Chinner <dchinner@xxxxxxxxxx>

Testing logarithmic paramters like "-n log=<num>" shows that we do a
terrible job of validating such input. e.g.:

# mkfs.xfs -f -n log=456858480 /dev/vda
.....
naming   =version 2              bsize=65536  ascii-ci=0 ftype=0
....

Yeah, I just asked for a block size of 2^456858480, and it didn't
get rejected. Great, isn't it?

So, factor out the parsing of logarithmic parameters, and pass in
the maximum valid value that they can take. These maximum values
might not be completely accurate (e.g. block/sector sizes will
affect the eventual valid maximum) but we can get rid of all the
overflows and stupidities before we get to fine-grained validity
checking later in mkfs once things like block and sector sizes have
been finalised.

Signed-off-by: Dave Chinner <dchinner@xxxxxxxxxx>
---
 mkfs/xfs_mkfs.c | 79 +++++++++++++++++++++++++++++++++++++--------------------
 1 file changed, 51 insertions(+), 28 deletions(-)

diff --git a/mkfs/xfs_mkfs.c b/mkfs/xfs_mkfs.c
index 126cbea..fbb2a35 100644
--- a/mkfs/xfs_mkfs.c
+++ b/mkfs/xfs_mkfs.c
@@ -982,6 +982,27 @@ getbool(
        return c ? true : false;
 }
 
+static int
+getnum_checked(
+       const char      *str,
+       long long       min_val,
+       long long       max_val,
+       const char      *illegal_str,
+       char            reqval_char,
+       char            *reqval_opts[],
+       int             reqval_optind)
+{
+       long long       c;
+
+       if (!str || *str == '\0')
+               reqval(reqval_char, reqval_opts, reqval_optind);
+
+       c = getnum(str, 0, 0, false);
+       if (c < min_val || c > max_val)
+               illegal(str, illegal_str);
+       return c;
+}
+
 int
 main(
        int                     argc,
@@ -1132,16 +1153,16 @@ main(
 
                                switch (getsubopt(&p, (constpp)bopts, &value)) {
                                case B_LOG:
-                                       if (!value || *value == '\0')
-                                               reqval('b', bopts, B_LOG);
                                        if (blflag)
                                                respec('b', bopts, B_LOG);
                                        if (bsflag)
                                                conflict('b', bopts, B_SIZE,
                                                         B_LOG);
-                                       blocklog = getnum(value, 0, 0, false);
-                                       if (blocklog <= 0)
-                                               illegal(value, "b log");
+                                       blocklog = getnum_checked(value,
+                                                       XFS_MIN_BLOCKSIZE_LOG,
+                                                       XFS_MAX_BLOCKSIZE_LOG,
+                                                       "b log", 'b', bopts,
+                                                       B_LOG);
                                        blocksize = 1 << blocklog;
                                        blflag = 1;
                                        break;
@@ -1278,16 +1299,16 @@ main(
                                        nodsflag = 1;
                                        break;
                                case D_SECTLOG:
-                                       if (!value || *value == '\0')
-                                               reqval('d', dopts, D_SECTLOG);
                                        if (slflag)
                                                respec('d', dopts, D_SECTLOG);
                                        if (ssflag)
                                                conflict('d', dopts, D_SECTSIZE,
                                                         D_SECTLOG);
-                                       sectorlog = getnum(value, 0, 0, false);
-                                       if (sectorlog <= 0)
-                                               illegal(value, "d sectlog");
+                                       sectorlog = getnum_checked(value,
+                                                       XFS_MIN_SECTORSIZE_LOG,
+                                                       XFS_MAX_SECTORSIZE_LOG,
+                                                       "d sectlog", 'd', dopts,
+                                                       D_SECTLOG);
                                        sectorsize = 1 << sectorlog;
                                        slflag = 1;
                                        break;
@@ -1352,9 +1373,11 @@ main(
                                        if (isflag)
                                                conflict('i', iopts, I_SIZE,
                                                         I_LOG);
-                                       inodelog = getnum(value, 0, 0, false);
-                                       if (inodelog <= 0)
-                                               illegal(value, "i log");
+                                       inodelog = getnum_checked(value,
+                                                       XFS_DINODE_MIN_LOG,
+                                                       XFS_DINODE_MAX_LOG,
+                                                       "i log", 'i', iopts,
+                                                       I_LOG);
                                        isize = 1 << inodelog;
                                        ilflag = 1;
                                        break;
@@ -1514,16 +1537,16 @@ main(
                                        lsflag = 1;
                                        break;
                                case L_SECTLOG:
-                                       if (!value || *value == '\0')
-                                               reqval('l', lopts, L_SECTLOG);
                                        if (lslflag)
                                                respec('l', lopts, L_SECTLOG);
                                        if (lssflag)
                                                conflict('l', lopts, L_SECTSIZE,
                                                         L_SECTLOG);
-                                       lsectorlog = getnum(value, 0, 0, false);
-                                       if (lsectorlog <= 0)
-                                               illegal(value, "l sectlog");
+                                       lsectorlog = getnum_checked(value,
+                                                       XFS_MIN_SECTORSIZE_LOG,
+                                                       XFS_MAX_SECTORSIZE_LOG,
+                                                       "l sectlog", 'l', lopts,
+                                                       L_SECTLOG);
                                        lsectorsize = 1 << lsectorlog;
                                        lslflag = 1;
                                        break;
@@ -1588,16 +1611,16 @@ _("cannot specify both -m crc=1 and -n ftype\n"));
 
                                switch (getsubopt(&p, (constpp)nopts, &value)) {
                                case N_LOG:
-                                       if (!value || *value == '\0')
-                                               reqval('n', nopts, N_LOG);
                                        if (nlflag)
                                                respec('n', nopts, N_LOG);
                                        if (nsflag)
                                                conflict('n', nopts, N_SIZE,
                                                         N_LOG);
-                                       dirblocklog = getnum(value, 0, 0, 
false);
-                                       if (dirblocklog <= 0)
-                                               illegal(value, "n log");
+                                       dirblocklog = getnum_checked(value,
+                                                       XFS_MIN_REC_DIRSIZE,
+                                                       XFS_MAX_BLOCKSIZE_LOG,
+                                                       "n log", 'n', nopts,
+                                                       N_LOG);
                                        dirblocksize = 1 << dirblocklog;
                                        nlflag = 1;
                                        break;
@@ -1716,16 +1739,16 @@ _("cannot specify both -m crc=1 and -n ftype\n"));
                                switch (getsubopt(&p, (constpp)sopts, &value)) {
                                case S_LOG:
                                case S_SECTLOG:
-                                       if (!value || *value == '\0')
-                                               reqval('s', sopts, S_SECTLOG);
                                        if (slflag || lslflag)
                                                respec('s', sopts, S_SECTLOG);
                                        if (ssflag || lssflag)
                                                conflict('s', sopts, S_SECTSIZE,
                                                         S_SECTLOG);
-                                       sectorlog = getnum(value, 0, 0, false);
-                                       if (sectorlog <= 0)
-                                               illegal(value, "s sectlog");
+                                       sectorlog = getnum_checked(value,
+                                                       XFS_MIN_SECTORSIZE_LOG,
+                                                       XFS_MAX_SECTORSIZE_LOG,
+                                                       "s sectlog", 's', sopts,
+                                                       S_SECTLOG);
                                        lsectorlog = sectorlog;
                                        sectorsize = 1 << sectorlog;
                                        lsectorsize = sectorsize;
-- 
1.8.4.rc3

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