From e35659f1b03c03946cae8abb6b0a9e170b574f1c Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Wed, 21 Dec 2016 14:32:19 +1100 Subject: [PATCH] NFSD: correctly range-check v4.x minor version when setting versions. Writing to /proc/fs/nfsd/versions allows individual major versions and NFSv4 minor versions to be enabled or disabled. However NFSv4.0 cannot currently be disabled, thought there is no good reason. Also the minor number is parsed as a 'long' but used as an 'int' so '4294967297' will be incorrectly treated as '1'. This patch removes the test on 'minor == 0' and switches to kstrtouint() to get correct range checking. When reading from /proc/fs/nfsd/versions, 4.0 is current not reported. To allow the disabling for v4.0 to be visible, while maintaining backward compatibility, change code to report "-4.0" if appropriate, but not "+4.0". Signed-off-by: NeilBrown Signed-off-by: J. Bruce Fields --- fs/nfsd/nfsctl.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c index f3b2f34b10a3..d54fb0e3f30e 100644 --- a/fs/nfsd/nfsctl.c +++ b/fs/nfsd/nfsctl.c @@ -569,8 +569,7 @@ static ssize_t __write_versions(struct file *file, char *buf, size_t size) if (*minorp == '.') { if (num != 4) return -EINVAL; - minor = simple_strtoul(minorp+1, NULL, 0); - if (minor == 0) + if (kstrtouint(minorp+1, 0, &minor) < 0) return -EINVAL; if (nfsd_minorversion(minor, sign == '-' ? NFSD_CLEAR : NFSD_SET) < 0) @@ -613,8 +612,13 @@ static ssize_t __write_versions(struct file *file, char *buf, size_t size) tlen += len; } if (nfsd_vers(4, NFSD_AVAIL)) - for (minor = 1; minor <= NFSD_SUPPORTED_MINOR_VERSION; + for (minor = 0; minor <= NFSD_SUPPORTED_MINOR_VERSION; minor++) { + if (minor == 0 && nfsd_minorversion(minor, NFSD_TEST)) + /* for backward compatibility, don't report + * +4.0 + */ + continue; len = snprintf(buf, remaining, " %c4.%u", (nfsd_vers(4, NFSD_TEST) && nfsd_minorversion(minor, NFSD_TEST)) ? -- 2.20.1