From: J. Bruce Fields <bfields@xxxxxxxxxxxxxx>
A uid or gid should be represented as unsigned, not signed.
The conversion to signed here could cause a hang on access by an unknown
user to a server running mountd with --manage-gids; such a user is
likely to be mapped to 2^32-1, which may be converted to 2^31-1 when
represented as an int, resulting in a downcall for uid 2^31-1, hence the
original rpc hanging forever waiting for a cache downcall for 2^32-1.
Signed-off-by: J. Bruce Fields <bfields@xxxxxxxxxxxxxx>
---
support/nfs/cacheio.c | 19 +++++++++++++++++++
utils/mountd/cache.c | 14 +++++++-------
2 files changed, 26 insertions(+), 7 deletions(-)
diff --git a/support/nfs/cacheio.c b/support/nfs/cacheio.c
index bdf5d84..0587ecb 100644
--- a/support/nfs/cacheio.c
+++ b/support/nfs/cacheio.c
@@ -148,6 +148,11 @@ void qword_printint(FILE *f, int num)
fprintf(f, "%d ", num);
}
+void qword_printuint(FILE *f, unsigned int num)
+{
+ fprintf(f, "%u ", num);
+}
+
int qword_eol(FILE *f)
{
int err;
@@ -236,6 +241,20 @@ int qword_get_int(char **bpp, int *anint)
return 0;
}
+int qword_get_uint(char *bpp, unsigned int *anint)
+{
+ char buf[50];
+ char *ep;
+ unsigned int rv;
+ int len = qword_get(bpp, buf, 50);
+ if (len < 0) return -1;
+ if (len ==0) return -1;
+ rv = strtoul(buf, &ep, 0);
+ if (*ep) return -1;
+ *anint = rv;
+ return 0;
+}
+
#define READLINE_BUFFER_INCREMENT 2048
int readline(int fd, char **buf, int *lenp)
diff --git a/utils/mountd/cache.c b/utils/mountd/cache.c
index 200e179..a6e0832 100644
--- a/utils/mountd/cache.c
+++ b/utils/mountd/cache.c
@@ -125,7 +125,7 @@ void auth_unix_gid(FILE *f)
* reply is
* uid expiry count list of group ids
*/
- int uid;
+ uid_t uid;
struct passwd *pw;
gid_t glist[100], *groups = glist;
int ngroups = 100;
@@ -136,7 +136,7 @@ void auth_unix_gid(FILE *f)
return;
cp = lbuf;
- if (qword_get_int(&cp, &uid) != 0)
+ if (qword_get_uint(&cp, &uid) != 0)
return;
pw = getpwuid(uid);
@@ -153,14 +153,14 @@ void auth_unix_gid(FILE *f)
groups, &ngroups);
}
}
- qword_printint(f, uid);
- qword_printint(f, time(0)+30*60);
+ qword_printuint(f, uid);
+ qword_printuint(f, time(0)+30*60);
if (rv >= 0) {
- qword_printint(f, ngroups);
+ qword_printuint(f, ngroups);
for (i=0; i<ngroups; i++)
- qword_printint(f, groups[i]);
+ qword_printuint(f, groups[i]);
} else
- qword_printint(f, 0);
+ qword_printuint(f, 0);
qword_eol(f);
if (groups != glist)
--
1.6.3.3
--
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