diff options
Diffstat (limited to 'src/lib9/convM2S.c')
| -rw-r--r-- | src/lib9/convM2S.c | 315 |
1 files changed, 315 insertions, 0 deletions
diff --git a/src/lib9/convM2S.c b/src/lib9/convM2S.c new file mode 100644 index 00000000..fcdcd42d --- /dev/null +++ b/src/lib9/convM2S.c @@ -0,0 +1,315 @@ +#include <u.h> +#include <libc.h> +#include <fcall.h> + +static +uchar* +gstring(uchar *p, uchar *ep, char **s) +{ + uint n; + + if(p+BIT16SZ > ep) + return nil; + n = GBIT16(p); + p += BIT16SZ - 1; + if(p+n+1 > ep) + return nil; + /* move it down, on top of count, to make room for '\0' */ + memmove(p, p + 1, n); + p[n] = '\0'; + *s = (char*)p; + p += n+1; + return p; +} + +static +uchar* +gqid(uchar *p, uchar *ep, Qid *q) +{ + if(p+QIDSZ > ep) + return nil; + q->type = GBIT8(p); + p += BIT8SZ; + q->vers = GBIT32(p); + p += BIT32SZ; + q->path = GBIT64(p); + p += BIT64SZ; + return p; +} + +/* + * no syntactic checks. + * three causes for error: + * 1. message size field is incorrect + * 2. input buffer too short for its own data (counts too long, etc.) + * 3. too many names or qids + * gqid() and gstring() return nil if they would reach beyond buffer. + * main switch statement checks range and also can fall through + * to test at end of routine. + */ +uint +convM2S(uchar *ap, uint nap, Fcall *f) +{ + uchar *p, *ep; + uint i, size; + + p = ap; + ep = p + nap; + + if(p+BIT32SZ+BIT8SZ+BIT16SZ > ep) + return 0; + size = GBIT32(p); + p += BIT32SZ; + + if(size < BIT32SZ+BIT8SZ+BIT16SZ) + return 0; + + f->type = GBIT8(p); + p += BIT8SZ; + f->tag = GBIT16(p); + p += BIT16SZ; + + switch(f->type) + { + default: + return 0; + + case Tversion: + if(p+BIT32SZ > ep) + return 0; + f->msize = GBIT32(p); + p += BIT32SZ; + p = gstring(p, ep, &f->version); + break; + + case Tflush: + if(p+BIT16SZ > ep) + return 0; + f->oldtag = GBIT16(p); + p += BIT16SZ; + break; + + case Tauth: + if(p+BIT32SZ > ep) + return 0; + f->afid = GBIT32(p); + p += BIT32SZ; + p = gstring(p, ep, &f->uname); + if(p == nil) + break; + p = gstring(p, ep, &f->aname); + if(p == nil) + break; + break; + + case Tattach: + if(p+BIT32SZ > ep) + return 0; + f->fid = GBIT32(p); + p += BIT32SZ; + if(p+BIT32SZ > ep) + return 0; + f->afid = GBIT32(p); + p += BIT32SZ; + p = gstring(p, ep, &f->uname); + if(p == nil) + break; + p = gstring(p, ep, &f->aname); + if(p == nil) + break; + break; + + case Twalk: + if(p+BIT32SZ+BIT32SZ+BIT16SZ > ep) + return 0; + f->fid = GBIT32(p); + p += BIT32SZ; + f->newfid = GBIT32(p); + p += BIT32SZ; + f->nwname = GBIT16(p); + p += BIT16SZ; + if(f->nwname > MAXWELEM) + return 0; + for(i=0; i<f->nwname; i++){ + p = gstring(p, ep, &f->wname[i]); + if(p == nil) + break; + } + break; + + case Topen: + if(p+BIT32SZ+BIT8SZ > ep) + return 0; + f->fid = GBIT32(p); + p += BIT32SZ; + f->mode = GBIT8(p); + p += BIT8SZ; + break; + + case Tcreate: + if(p+BIT32SZ > ep) + return 0; + f->fid = GBIT32(p); + p += BIT32SZ; + p = gstring(p, ep, &f->name); + if(p == nil) + break; + if(p+BIT32SZ+BIT8SZ > ep) + return 0; + f->perm = GBIT32(p); + p += BIT32SZ; + f->mode = GBIT8(p); + p += BIT8SZ; + break; + + case Tread: + if(p+BIT32SZ+BIT64SZ+BIT32SZ > ep) + return 0; + f->fid = GBIT32(p); + p += BIT32SZ; + f->offset = GBIT64(p); + p += BIT64SZ; + f->count = GBIT32(p); + p += BIT32SZ; + break; + + case Twrite: + if(p+BIT32SZ+BIT64SZ+BIT32SZ > ep) + return 0; + f->fid = GBIT32(p); + p += BIT32SZ; + f->offset = GBIT64(p); + p += BIT64SZ; + f->count = GBIT32(p); + p += BIT32SZ; + if(p+f->count > ep) + return 0; + f->data = (char*)p; + p += f->count; + break; + + case Tclunk: + case Tremove: + if(p+BIT32SZ > ep) + return 0; + f->fid = GBIT32(p); + p += BIT32SZ; + break; + + case Tstat: + if(p+BIT32SZ > ep) + return 0; + f->fid = GBIT32(p); + p += BIT32SZ; + break; + + case Twstat: + if(p+BIT32SZ+BIT16SZ > ep) + return 0; + f->fid = GBIT32(p); + p += BIT32SZ; + f->nstat = GBIT16(p); + p += BIT16SZ; + if(p+f->nstat > ep) + return 0; + f->stat = p; + p += f->nstat; + break; + +/* + */ + case Rversion: + if(p+BIT32SZ > ep) + return 0; + f->msize = GBIT32(p); + p += BIT32SZ; + p = gstring(p, ep, &f->version); + break; + + case Rerror: + p = gstring(p, ep, &f->ename); + break; + + case Rflush: + break; + + case Rauth: + p = gqid(p, ep, &f->aqid); + if(p == nil) + break; + break; + + case Rattach: + p = gqid(p, ep, &f->qid); + if(p == nil) + break; + break; + + case Rwalk: + if(p+BIT16SZ > ep) + return 0; + f->nwqid = GBIT16(p); + p += BIT16SZ; + if(f->nwqid > MAXWELEM) + return 0; + for(i=0; i<f->nwqid; i++){ + p = gqid(p, ep, &f->wqid[i]); + if(p == nil) + break; + } + break; + + case Ropen: + case Rcreate: + p = gqid(p, ep, &f->qid); + if(p == nil) + break; + if(p+BIT32SZ > ep) + return 0; + f->iounit = GBIT32(p); + p += BIT32SZ; + break; + + case Rread: + if(p+BIT32SZ > ep) + return 0; + f->count = GBIT32(p); + p += BIT32SZ; + if(p+f->count > ep) + return 0; + f->data = (char*)p; + p += f->count; + break; + + case Rwrite: + if(p+BIT32SZ > ep) + return 0; + f->count = GBIT32(p); + p += BIT32SZ; + break; + + case Rclunk: + case Rremove: + break; + + case Rstat: + if(p+BIT16SZ > ep) + return 0; + f->nstat = GBIT16(p); + p += BIT16SZ; + if(p+f->nstat > ep) + return 0; + f->stat = p; + p += f->nstat; + break; + + case Rwstat: + break; + } + + if(p==nil || p>ep) + return 0; + if(ap+size == p) + return size; + return 0; +} |