| Message ID | 1471368517-20552-8-git-send-email-william.c.roberts@intel.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
> -----Original Message----- > From: Roberts, William C > Sent: Tuesday, August 16, 2016 10:29 AM > To: selinux@tycho.nsa.gov; jwcart2@tycho.nsa.gov; seandroid- > list@tycho.nsa.gov; sds@tycho.nsa.gov > Cc: Roberts, William C <william.c.roberts@intel.com> > Subject: [PATCH v4 7/7] libsepol: fix overflow and 0 length allocations > > From: William Roberts <william.c.roberts@intel.com> > > Throughout libsepol, values taken from sepolicy are used in places where length > == 0 or length == <saturated> matter, find and fix these. > > Also, correct any type mismatches noticed along the way. > > Signed-off-by: William Roberts <william.c.roberts@intel.com> > --- > libsepol/src/conditional.c | 3 +- > libsepol/src/context.c | 16 +++++++--- > libsepol/src/context_record.c | 72 +++++++++++++++++++++++++++++---------- > ---- > libsepol/src/module.c | 13 ++++++++ > libsepol/src/module_to_cil.c | 4 ++- > libsepol/src/policydb.c | 52 +++++++++++++++++++++++++++++-- > libsepol/src/private.h | 3 ++ > 7 files changed, 130 insertions(+), 33 deletions(-) > > diff --git a/libsepol/src/conditional.c b/libsepol/src/conditional.c index > ea47cdd..8680eb2 100644 > --- a/libsepol/src/conditional.c > +++ b/libsepol/src/conditional.c > @@ -589,7 +589,8 @@ int cond_read_bool(policydb_t * p, > goto err; > > len = le32_to_cpu(buf[2]); > - > + if (zero_or_saturated(len)) > + goto err; > key = malloc(len + 1); > if (!key) > goto err; > diff --git a/libsepol/src/context.c b/libsepol/src/context.c index 420ee16..a88937f > 100644 > --- a/libsepol/src/context.c > +++ b/libsepol/src/context.c > @@ -10,6 +10,7 @@ > #include "context.h" > #include "handle.h" > #include "mls.h" > +#include "private.h" > > /* ----- Compatibility ---- */ > int policydb_context_isvalid(const policydb_t * p, const context_struct_t * c) > @@ -297,10 +298,18 @@ int context_from_string(sepol_handle_t * handle, > char *con_cpy = NULL; > sepol_context_t *ctx_record = NULL; > > + if (zero_or_saturated(con_str_len)) { > + ERR(handle, "Invalid context length"); > + goto err; > + } > + > /* sepol_context_from_string expects a NULL-terminated string */ > con_cpy = malloc(con_str_len + 1); > - if (!con_cpy) > - goto omem; > + if (!con_cpy) { > + ERR(handle, "out of memory"); > + goto err; > + } > + > memcpy(con_cpy, con_str, con_str_len); > con_cpy[con_str_len] = '\0'; > > @@ -315,9 +324,6 @@ int context_from_string(sepol_handle_t * handle, > sepol_context_free(ctx_record); > return STATUS_SUCCESS; > > - omem: > - ERR(handle, "out of memory"); > - > err: > ERR(handle, "could not create context structure"); > free(con_cpy); > diff --git a/libsepol/src/context_record.c b/libsepol/src/context_record.c index > ac2884a..0a8bbf6 100644 > --- a/libsepol/src/context_record.c > +++ b/libsepol/src/context_record.c > @@ -5,6 +5,7 @@ > > #include "context_internal.h" > #include "debug.h" > +#include "private.h" > > struct sepol_context { > > @@ -279,44 +280,69 @@ int sepol_context_from_string(sepol_handle_t * > handle, > > hidden_def(sepol_context_from_string) > > +static inline int safe_sum(size_t *sum, const size_t augends[], const > +size_t cnt) { > + > + size_t a, i; > + > + *sum = 0; > + for(i=0; i < cnt; i++) { > + /* sum should not be smaller than the addend */ > + a = augends[i]; > + *sum += a; > + if (*sum < a) { > + return i; Damn it...this does not work when index 0 is the bad one... I'll wait till Tomorrow and aggregate responses again. > + } > + } > + > + return 0; > +} > + > int sepol_context_to_string(sepol_handle_t * handle, > const sepol_context_t * con, char **str_ptr) { > > int rc; > - const int user_sz = strlen(con->user); > - const int role_sz = strlen(con->role); > - const int type_sz = strlen(con->type); > - const int mls_sz = (con->mls) ? strlen(con->mls) : 0; > - const int total_sz = user_sz + role_sz + type_sz + > - mls_sz + ((con->mls) ? 3 : 2); > - > - char *str = (char *)malloc(total_sz + 1); > - if (!str) > - goto omem; > + char *str = NULL; > + size_t total_sz, err; > + const size_t sizes[] = { > + strlen(con->user), /* user length */ > + strlen(con->role), /* role length */ > + strlen(con->type), /* type length */ > + (con->mls) ? strlen(con->mls) : 0, /* mls length */ > + ((con->mls) ? 3 : 2) + 1 /* mls has extra ":" also null > byte */ > + }; > + > + err = safe_sum(&total_sz, sizes, ARRAY_SIZE(sizes)); > + if (err) { > + ERR(handle, "invalid size, overflow at position: %zu", err); > + goto err; > + } > > + str = (char *)malloc(total_sz); > + if (!str) { > + ERR(handle, "out of memory"); > + goto err; > + } > if (con->mls) { > - rc = snprintf(str, total_sz + 1, "%s:%s:%s:%s", > + rc = snprintf(str, total_sz, "%s:%s:%s:%s", > con->user, con->role, con->type, con->mls); > - if (rc < 0 || (rc >= total_sz + 1)) { > - ERR(handle, "print error"); > - goto err; > - } > } else { > - rc = snprintf(str, total_sz + 1, "%s:%s:%s", > + rc = snprintf(str, total_sz, "%s:%s:%s", > con->user, con->role, con->type); > - if (rc < 0 || (rc >= total_sz + 1)) { > - ERR(handle, "print error"); > - goto err; > - } > + } > + > + /* > + * rc is >= 0 on the size_t cast and is safe to promote > + * to an unsigned value. > + */ > + if (rc < 0 || (size_t)rc >= total_sz) { > + ERR(handle, "print error"); > + goto err; > } > > *str_ptr = str; > return STATUS_SUCCESS; > > - omem: > - ERR(handle, "out of memory"); > - > err: > ERR(handle, "could not convert context to string"); > free(str); > diff --git a/libsepol/src/module.c b/libsepol/src/module.c index 1665ede..f25df95 > 100644 > --- a/libsepol/src/module.c > +++ b/libsepol/src/module.c > @@ -30,6 +30,7 @@ > #include <stdio.h> > #include <stdlib.h> > #include <limits.h> > +#include <inttypes.h> > > #define SEPOL_PACKAGE_SECTION_FC 0xf97cff90 #define > SEPOL_PACKAGE_SECTION_SEUSER 0x97cff91 @@ -793,6 +794,12 @@ int > sepol_module_package_info(struct sepol_policy_file *spf, int *type, > goto cleanup; > } > len = le32_to_cpu(buf[0]); > + if (zero_or_saturated(len)) { > + ERR(file->handle, > + "invalid module name length: 0x%"PRIx32, > + len); > + goto cleanup; > + } > *name = malloc(len + 1); > if (!*name) { > ERR(file->handle, "out of memory"); @@ -814,6 > +821,12 @@ int sepol_module_package_info(struct sepol_policy_file *spf, int > *type, > goto cleanup; > } > len = le32_to_cpu(buf[0]); > + if (zero_or_saturated(len)) { > + ERR(file->handle, > + "invalid module version length: 0x%"PRIx32, > + len); > + goto cleanup; > + } > *version = malloc(len + 1); > if (!*version) { > ERR(file->handle, "out of memory"); diff --git > a/libsepol/src/module_to_cil.c b/libsepol/src/module_to_cil.c index > 36f3b7d..fc65019 100644 > --- a/libsepol/src/module_to_cil.c > +++ b/libsepol/src/module_to_cil.c > @@ -47,6 +47,8 @@ > #include <sepol/policydb/services.h> > #include <sepol/policydb/util.h> > > +#include "private.h" > + > #ifdef __GNUC__ > # define UNUSED(x) UNUSED_ ## x __attribute__((__unused__)) #else @@ - > 124,7 +126,7 @@ static int get_line(char **start, char *end, char **line) > > for (len = 0; p < end && *p != '\n' && *p != '\0'; p++, len++); > > - if (len == 0) { > + if (zero_or_saturated(len)) { > rc = 0; > goto exit; > } > diff --git a/libsepol/src/policydb.c b/libsepol/src/policydb.c index > 60761b7..c225ac6 100644 > --- a/libsepol/src/policydb.c > +++ b/libsepol/src/policydb.c > @@ -1911,6 +1911,9 @@ static int perm_read(policydb_t * p > goto bad; > > len = le32_to_cpu(buf[0]); > + if (zero_or_saturated(len)) > + goto bad; > + > perdatum->s.value = le32_to_cpu(buf[1]); > > key = malloc(len + 1); > @@ -1949,6 +1952,9 @@ static int common_read(policydb_t * p, hashtab_t h, > struct policy_file *fp) > goto bad; > > len = le32_to_cpu(buf[0]); > + if (zero_or_saturated(len)) > + goto bad; > + > comdatum->s.value = le32_to_cpu(buf[1]); > > if (symtab_init(&comdatum->permissions, PERM_SYMTAB_SIZE)) @@ - > 2092,7 +2098,11 @@ static int class_read(policydb_t * p, hashtab_t h, struct > policy_file *fp) > goto bad; > > len = le32_to_cpu(buf[0]); > + if (zero_or_saturated(len)) > + goto bad; > len2 = le32_to_cpu(buf[1]); > + if (is_saturated(len2)) > + goto bad; > cladatum->s.value = le32_to_cpu(buf[2]); > > if (symtab_init(&cladatum->permissions, PERM_SYMTAB_SIZE)) @@ - > 2199,6 +2209,9 @@ static int role_read(policydb_t * p, hashtab_t h, struct > policy_file *fp) > goto bad; > > len = le32_to_cpu(buf[0]); > + if (zero_or_saturated(len)) > + goto bad; > + > role->s.value = le32_to_cpu(buf[1]); > if (policydb_has_boundary_feature(p)) > role->bounds = le32_to_cpu(buf[2]); > @@ -2287,6 +2300,9 @@ static int type_read(policydb_t * p, hashtab_t h, struct > policy_file *fp) > goto bad; > > len = le32_to_cpu(buf[pos]); > + if (zero_or_saturated(len)) > + goto bad; > + > typdatum->s.value = le32_to_cpu(buf[++pos]); > if (policydb_has_boundary_feature(p)) { > uint32_t properties; > @@ -2447,6 +2463,8 @@ int filename_trans_read(filename_trans_t **t, struct > policy_file *fp) > if (rc < 0) > return -1; > len = le32_to_cpu(buf[0]); > + if (zero_or_saturated(len)) > + return -1; > > name = calloc(len + 1, sizeof(*name)); > if (!name) > @@ -2556,6 +2574,9 @@ static int ocontext_read_xen(struct > policydb_compat_info *info, > if (rc < 0) > return -1; > len = le32_to_cpu(buf[0]); > + if (zero_or_saturated(len)) > + return -1; > + > c->u.name = malloc(len + 1); > if (!c->u.name) > return -1; > @@ -2618,6 +2639,8 @@ static int ocontext_read_selinux(struct > policydb_compat_info *info, > if (rc < 0) > return -1; > len = le32_to_cpu(buf[0]); > + if (zero_or_saturated(len)) > + return -1; > c->u.name = malloc(len + 1); > if (!c->u.name) > return -1; > @@ -2659,6 +2682,8 @@ static int ocontext_read_selinux(struct > policydb_compat_info *info, > return -1; > c->v.behavior = le32_to_cpu(buf[0]); > len = le32_to_cpu(buf[1]); > + if (zero_or_saturated(len)) > + return -1; > c->u.name = malloc(len + 1); > if (!c->u.name) > return -1; > @@ -2719,7 +2744,7 @@ static int genfs_read(policydb_t * p, struct policy_file > *fp) > uint32_t buf[1]; > size_t nel, nel2, len, len2; > genfs_t *genfs_p, *newgenfs, *genfs; > - unsigned int i, j; > + size_t i, j; > ocontext_t *l, *c, *newc = NULL; > int rc; > > @@ -2733,6 +2758,8 @@ static int genfs_read(policydb_t * p, struct policy_file > *fp) > if (rc < 0) > goto bad; > len = le32_to_cpu(buf[0]); > + if (zero_or_saturated(len)) > + goto bad; > newgenfs = calloc(1, sizeof(genfs_t)); > if (!newgenfs) > goto bad; > @@ -2778,6 +2805,8 @@ static int genfs_read(policydb_t * p, struct policy_file > *fp) > if (rc < 0) > goto bad; > len = le32_to_cpu(buf[0]); > + if (zero_or_saturated(len)) > + goto bad; > newc->u.name = malloc(len + 1); > if (!newc->u.name) { > goto bad; > @@ -2877,6 +2906,9 @@ static int user_read(policydb_t * p, hashtab_t h, struct > policy_file *fp) > goto bad; > > len = le32_to_cpu(buf[0]); > + if (zero_or_saturated(len)) > + goto bad; > + > usrdatum->s.value = le32_to_cpu(buf[1]); > if (policydb_has_boundary_feature(p)) > usrdatum->bounds = le32_to_cpu(buf[2]); @@ -2960,6 +2992,9 > @@ static int sens_read(policydb_t * p > goto bad; > > len = le32_to_cpu(buf[0]); > + if (zero_or_saturated(len)) > + goto bad; > + > levdatum->isalias = le32_to_cpu(buf[1]); > > key = malloc(len + 1); > @@ -3003,6 +3038,9 @@ static int cat_read(policydb_t * p > goto bad; > > len = le32_to_cpu(buf[0]); > + if(zero_or_saturated(len)) > + goto bad; > + > catdatum->s.value = le32_to_cpu(buf[1]); > catdatum->isalias = le32_to_cpu(buf[2]); > > @@ -3339,6 +3377,8 @@ static int > filename_trans_rule_read(filename_trans_rule_t ** r, struct policy_fi > return -1; > > len = le32_to_cpu(buf[0]); > + if (zero_or_saturated(len)) > + return -1; > > ftr->name = malloc(len + 1); > if (!ftr->name) > @@ -3580,6 +3620,8 @@ static int scope_read(policydb_t * p, int symnum, struct > policy_file *fp) > if (rc < 0) > goto cleanup; > key_len = le32_to_cpu(buf[0]); > + if (zero_or_saturated(key_len)) > + goto cleanup; > key = malloc(key_len + 1); > if (!key) > goto cleanup; > @@ -3664,8 +3706,8 @@ int policydb_read(policydb_t * p, struct policy_file *fp, > unsigned verbose) > } > > len = buf[1]; > - if (len > POLICYDB_STRING_MAX_LENGTH) { > - ERR(fp->handle, "policydb string length too long "); > + if (len == 0 || len > POLICYDB_STRING_MAX_LENGTH) { > + ERR(fp->handle, "policydb string length %s ", len ? "too long" : > +"zero"); > return POLICYDB_ERROR; > } > > @@ -3798,6 +3840,8 @@ int policydb_read(policydb_t * p, struct policy_file *fp, > unsigned verbose) > goto bad; > } > len = le32_to_cpu(buf[0]); > + if (zero_or_saturated(len)) > + goto bad; > if ((p->name = malloc(len + 1)) == NULL) { > goto bad; > } > @@ -3809,6 +3853,8 @@ int policydb_read(policydb_t * p, struct policy_file *fp, > unsigned verbose) > goto bad; > } > len = le32_to_cpu(buf[0]); > + if (zero_or_saturated(len)) > + goto bad; > if ((p->version = malloc(len + 1)) == NULL) { > goto bad; > } > diff --git a/libsepol/src/private.h b/libsepol/src/private.h index 9c700c9..0beb4d4 > 100644 > --- a/libsepol/src/private.h > +++ b/libsepol/src/private.h > @@ -45,6 +45,9 @@ > > #define ARRAY_SIZE(x) (sizeof(x)/sizeof((x)[0])) > > +#define is_saturated(x) (x == (typeof(x))-1) #define > +zero_or_saturated(x) ((x == 0) || is_saturated(x)) > + > /* Policy compatibility information. */ struct policydb_compat_info { > unsigned int type; > -- > 1.9.1
On 08/16/2016 01:45 PM, Roberts, William C wrote: > > >> -----Original Message----- >> From: Roberts, William C >> Sent: Tuesday, August 16, 2016 10:29 AM >> To: selinux@tycho.nsa.gov; jwcart2@tycho.nsa.gov; seandroid- >> list@tycho.nsa.gov; sds@tycho.nsa.gov >> Cc: Roberts, William C <william.c.roberts@intel.com> >> Subject: [PATCH v4 7/7] libsepol: fix overflow and 0 length allocations >> >> From: William Roberts <william.c.roberts@intel.com> >> >> Throughout libsepol, values taken from sepolicy are used in places where length >> == 0 or length == <saturated> matter, find and fix these. >> >> Also, correct any type mismatches noticed along the way. >> >> Signed-off-by: William Roberts <william.c.roberts@intel.com> >> --- >> libsepol/src/conditional.c | 3 +- >> libsepol/src/context.c | 16 +++++++--- >> libsepol/src/context_record.c | 72 +++++++++++++++++++++++++++++---------- >> ---- >> libsepol/src/module.c | 13 ++++++++ >> libsepol/src/module_to_cil.c | 4 ++- >> libsepol/src/policydb.c | 52 +++++++++++++++++++++++++++++-- >> libsepol/src/private.h | 3 ++ >> 7 files changed, 130 insertions(+), 33 deletions(-) >> >> diff --git a/libsepol/src/conditional.c b/libsepol/src/conditional.c index >> ea47cdd..8680eb2 100644 >> --- a/libsepol/src/conditional.c >> +++ b/libsepol/src/conditional.c >> @@ -589,7 +589,8 @@ int cond_read_bool(policydb_t * p, >> goto err; >> >> len = le32_to_cpu(buf[2]); >> - >> + if (zero_or_saturated(len)) >> + goto err; >> key = malloc(len + 1); >> if (!key) >> goto err; >> diff --git a/libsepol/src/context.c b/libsepol/src/context.c index 420ee16..a88937f >> 100644 >> --- a/libsepol/src/context.c >> +++ b/libsepol/src/context.c >> @@ -10,6 +10,7 @@ >> #include "context.h" >> #include "handle.h" >> #include "mls.h" >> +#include "private.h" >> >> /* ----- Compatibility ---- */ >> int policydb_context_isvalid(const policydb_t * p, const context_struct_t * c) >> @@ -297,10 +298,18 @@ int context_from_string(sepol_handle_t * handle, >> char *con_cpy = NULL; >> sepol_context_t *ctx_record = NULL; >> >> + if (zero_or_saturated(con_str_len)) { >> + ERR(handle, "Invalid context length"); >> + goto err; >> + } >> + >> /* sepol_context_from_string expects a NULL-terminated string */ >> con_cpy = malloc(con_str_len + 1); >> - if (!con_cpy) >> - goto omem; >> + if (!con_cpy) { >> + ERR(handle, "out of memory"); >> + goto err; >> + } >> + >> memcpy(con_cpy, con_str, con_str_len); >> con_cpy[con_str_len] = '\0'; >> >> @@ -315,9 +324,6 @@ int context_from_string(sepol_handle_t * handle, >> sepol_context_free(ctx_record); >> return STATUS_SUCCESS; >> >> - omem: >> - ERR(handle, "out of memory"); >> - >> err: >> ERR(handle, "could not create context structure"); >> free(con_cpy); >> diff --git a/libsepol/src/context_record.c b/libsepol/src/context_record.c index >> ac2884a..0a8bbf6 100644 >> --- a/libsepol/src/context_record.c >> +++ b/libsepol/src/context_record.c >> @@ -5,6 +5,7 @@ >> >> #include "context_internal.h" >> #include "debug.h" >> +#include "private.h" >> >> struct sepol_context { >> >> @@ -279,44 +280,69 @@ int sepol_context_from_string(sepol_handle_t * >> handle, >> >> hidden_def(sepol_context_from_string) >> >> +static inline int safe_sum(size_t *sum, const size_t augends[], const >> +size_t cnt) { >> + >> + size_t a, i; >> + >> + *sum = 0; >> + for(i=0; i < cnt; i++) { >> + /* sum should not be smaller than the addend */ >> + a = augends[i]; >> + *sum += a; >> + if (*sum < a) { >> + return i; > > Damn it...this does not work when index 0 is the bad one... I'll wait till > Tomorrow and aggregate responses again. Use __builtin_add_overflow()?
diff --git a/libsepol/src/conditional.c b/libsepol/src/conditional.c index ea47cdd..8680eb2 100644 --- a/libsepol/src/conditional.c +++ b/libsepol/src/conditional.c @@ -589,7 +589,8 @@ int cond_read_bool(policydb_t * p, goto err; len = le32_to_cpu(buf[2]); - + if (zero_or_saturated(len)) + goto err; key = malloc(len + 1); if (!key) goto err; diff --git a/libsepol/src/context.c b/libsepol/src/context.c index 420ee16..a88937f 100644 --- a/libsepol/src/context.c +++ b/libsepol/src/context.c @@ -10,6 +10,7 @@ #include "context.h" #include "handle.h" #include "mls.h" +#include "private.h" /* ----- Compatibility ---- */ int policydb_context_isvalid(const policydb_t * p, const context_struct_t * c) @@ -297,10 +298,18 @@ int context_from_string(sepol_handle_t * handle, char *con_cpy = NULL; sepol_context_t *ctx_record = NULL; + if (zero_or_saturated(con_str_len)) { + ERR(handle, "Invalid context length"); + goto err; + } + /* sepol_context_from_string expects a NULL-terminated string */ con_cpy = malloc(con_str_len + 1); - if (!con_cpy) - goto omem; + if (!con_cpy) { + ERR(handle, "out of memory"); + goto err; + } + memcpy(con_cpy, con_str, con_str_len); con_cpy[con_str_len] = '\0'; @@ -315,9 +324,6 @@ int context_from_string(sepol_handle_t * handle, sepol_context_free(ctx_record); return STATUS_SUCCESS; - omem: - ERR(handle, "out of memory"); - err: ERR(handle, "could not create context structure"); free(con_cpy); diff --git a/libsepol/src/context_record.c b/libsepol/src/context_record.c index ac2884a..0a8bbf6 100644 --- a/libsepol/src/context_record.c +++ b/libsepol/src/context_record.c @@ -5,6 +5,7 @@ #include "context_internal.h" #include "debug.h" +#include "private.h" struct sepol_context { @@ -279,44 +280,69 @@ int sepol_context_from_string(sepol_handle_t * handle, hidden_def(sepol_context_from_string) +static inline int safe_sum(size_t *sum, const size_t augends[], const size_t cnt) { + + size_t a, i; + + *sum = 0; + for(i=0; i < cnt; i++) { + /* sum should not be smaller than the addend */ + a = augends[i]; + *sum += a; + if (*sum < a) { + return i; + } + } + + return 0; +} + int sepol_context_to_string(sepol_handle_t * handle, const sepol_context_t * con, char **str_ptr) { int rc; - const int user_sz = strlen(con->user); - const int role_sz = strlen(con->role); - const int type_sz = strlen(con->type); - const int mls_sz = (con->mls) ? strlen(con->mls) : 0; - const int total_sz = user_sz + role_sz + type_sz + - mls_sz + ((con->mls) ? 3 : 2); - - char *str = (char *)malloc(total_sz + 1); - if (!str) - goto omem; + char *str = NULL; + size_t total_sz, err; + const size_t sizes[] = { + strlen(con->user), /* user length */ + strlen(con->role), /* role length */ + strlen(con->type), /* type length */ + (con->mls) ? strlen(con->mls) : 0, /* mls length */ + ((con->mls) ? 3 : 2) + 1 /* mls has extra ":" also null byte */ + }; + + err = safe_sum(&total_sz, sizes, ARRAY_SIZE(sizes)); + if (err) { + ERR(handle, "invalid size, overflow at position: %zu", err); + goto err; + } + str = (char *)malloc(total_sz); + if (!str) { + ERR(handle, "out of memory"); + goto err; + } if (con->mls) { - rc = snprintf(str, total_sz + 1, "%s:%s:%s:%s", + rc = snprintf(str, total_sz, "%s:%s:%s:%s", con->user, con->role, con->type, con->mls); - if (rc < 0 || (rc >= total_sz + 1)) { - ERR(handle, "print error"); - goto err; - } } else { - rc = snprintf(str, total_sz + 1, "%s:%s:%s", + rc = snprintf(str, total_sz, "%s:%s:%s", con->user, con->role, con->type); - if (rc < 0 || (rc >= total_sz + 1)) { - ERR(handle, "print error"); - goto err; - } + } + + /* + * rc is >= 0 on the size_t cast and is safe to promote + * to an unsigned value. + */ + if (rc < 0 || (size_t)rc >= total_sz) { + ERR(handle, "print error"); + goto err; } *str_ptr = str; return STATUS_SUCCESS; - omem: - ERR(handle, "out of memory"); - err: ERR(handle, "could not convert context to string"); free(str); diff --git a/libsepol/src/module.c b/libsepol/src/module.c index 1665ede..f25df95 100644 --- a/libsepol/src/module.c +++ b/libsepol/src/module.c @@ -30,6 +30,7 @@ #include <stdio.h> #include <stdlib.h> #include <limits.h> +#include <inttypes.h> #define SEPOL_PACKAGE_SECTION_FC 0xf97cff90 #define SEPOL_PACKAGE_SECTION_SEUSER 0x97cff91 @@ -793,6 +794,12 @@ int sepol_module_package_info(struct sepol_policy_file *spf, int *type, goto cleanup; } len = le32_to_cpu(buf[0]); + if (zero_or_saturated(len)) { + ERR(file->handle, + "invalid module name length: 0x%"PRIx32, + len); + goto cleanup; + } *name = malloc(len + 1); if (!*name) { ERR(file->handle, "out of memory"); @@ -814,6 +821,12 @@ int sepol_module_package_info(struct sepol_policy_file *spf, int *type, goto cleanup; } len = le32_to_cpu(buf[0]); + if (zero_or_saturated(len)) { + ERR(file->handle, + "invalid module version length: 0x%"PRIx32, + len); + goto cleanup; + } *version = malloc(len + 1); if (!*version) { ERR(file->handle, "out of memory"); diff --git a/libsepol/src/module_to_cil.c b/libsepol/src/module_to_cil.c index 36f3b7d..fc65019 100644 --- a/libsepol/src/module_to_cil.c +++ b/libsepol/src/module_to_cil.c @@ -47,6 +47,8 @@ #include <sepol/policydb/services.h> #include <sepol/policydb/util.h> +#include "private.h" + #ifdef __GNUC__ # define UNUSED(x) UNUSED_ ## x __attribute__((__unused__)) #else @@ -124,7 +126,7 @@ static int get_line(char **start, char *end, char **line) for (len = 0; p < end && *p != '\n' && *p != '\0'; p++, len++); - if (len == 0) { + if (zero_or_saturated(len)) { rc = 0; goto exit; } diff --git a/libsepol/src/policydb.c b/libsepol/src/policydb.c index 60761b7..c225ac6 100644 --- a/libsepol/src/policydb.c +++ b/libsepol/src/policydb.c @@ -1911,6 +1911,9 @@ static int perm_read(policydb_t * p goto bad; len = le32_to_cpu(buf[0]); + if (zero_or_saturated(len)) + goto bad; + perdatum->s.value = le32_to_cpu(buf[1]); key = malloc(len + 1); @@ -1949,6 +1952,9 @@ static int common_read(policydb_t * p, hashtab_t h, struct policy_file *fp) goto bad; len = le32_to_cpu(buf[0]); + if (zero_or_saturated(len)) + goto bad; + comdatum->s.value = le32_to_cpu(buf[1]); if (symtab_init(&comdatum->permissions, PERM_SYMTAB_SIZE)) @@ -2092,7 +2098,11 @@ static int class_read(policydb_t * p, hashtab_t h, struct policy_file *fp) goto bad; len = le32_to_cpu(buf[0]); + if (zero_or_saturated(len)) + goto bad; len2 = le32_to_cpu(buf[1]); + if (is_saturated(len2)) + goto bad; cladatum->s.value = le32_to_cpu(buf[2]); if (symtab_init(&cladatum->permissions, PERM_SYMTAB_SIZE)) @@ -2199,6 +2209,9 @@ static int role_read(policydb_t * p, hashtab_t h, struct policy_file *fp) goto bad; len = le32_to_cpu(buf[0]); + if (zero_or_saturated(len)) + goto bad; + role->s.value = le32_to_cpu(buf[1]); if (policydb_has_boundary_feature(p)) role->bounds = le32_to_cpu(buf[2]); @@ -2287,6 +2300,9 @@ static int type_read(policydb_t * p, hashtab_t h, struct policy_file *fp) goto bad; len = le32_to_cpu(buf[pos]); + if (zero_or_saturated(len)) + goto bad; + typdatum->s.value = le32_to_cpu(buf[++pos]); if (policydb_has_boundary_feature(p)) { uint32_t properties; @@ -2447,6 +2463,8 @@ int filename_trans_read(filename_trans_t **t, struct policy_file *fp) if (rc < 0) return -1; len = le32_to_cpu(buf[0]); + if (zero_or_saturated(len)) + return -1; name = calloc(len + 1, sizeof(*name)); if (!name) @@ -2556,6 +2574,9 @@ static int ocontext_read_xen(struct policydb_compat_info *info, if (rc < 0) return -1; len = le32_to_cpu(buf[0]); + if (zero_or_saturated(len)) + return -1; + c->u.name = malloc(len + 1); if (!c->u.name) return -1; @@ -2618,6 +2639,8 @@ static int ocontext_read_selinux(struct policydb_compat_info *info, if (rc < 0) return -1; len = le32_to_cpu(buf[0]); + if (zero_or_saturated(len)) + return -1; c->u.name = malloc(len + 1); if (!c->u.name) return -1; @@ -2659,6 +2682,8 @@ static int ocontext_read_selinux(struct policydb_compat_info *info, return -1; c->v.behavior = le32_to_cpu(buf[0]); len = le32_to_cpu(buf[1]); + if (zero_or_saturated(len)) + return -1; c->u.name = malloc(len + 1); if (!c->u.name) return -1; @@ -2719,7 +2744,7 @@ static int genfs_read(policydb_t * p, struct policy_file *fp) uint32_t buf[1]; size_t nel, nel2, len, len2; genfs_t *genfs_p, *newgenfs, *genfs; - unsigned int i, j; + size_t i, j; ocontext_t *l, *c, *newc = NULL; int rc; @@ -2733,6 +2758,8 @@ static int genfs_read(policydb_t * p, struct policy_file *fp) if (rc < 0) goto bad; len = le32_to_cpu(buf[0]); + if (zero_or_saturated(len)) + goto bad; newgenfs = calloc(1, sizeof(genfs_t)); if (!newgenfs) goto bad; @@ -2778,6 +2805,8 @@ static int genfs_read(policydb_t * p, struct policy_file *fp) if (rc < 0) goto bad; len = le32_to_cpu(buf[0]); + if (zero_or_saturated(len)) + goto bad; newc->u.name = malloc(len + 1); if (!newc->u.name) { goto bad; @@ -2877,6 +2906,9 @@ static int user_read(policydb_t * p, hashtab_t h, struct policy_file *fp) goto bad; len = le32_to_cpu(buf[0]); + if (zero_or_saturated(len)) + goto bad; + usrdatum->s.value = le32_to_cpu(buf[1]); if (policydb_has_boundary_feature(p)) usrdatum->bounds = le32_to_cpu(buf[2]); @@ -2960,6 +2992,9 @@ static int sens_read(policydb_t * p goto bad; len = le32_to_cpu(buf[0]); + if (zero_or_saturated(len)) + goto bad; + levdatum->isalias = le32_to_cpu(buf[1]); key = malloc(len + 1); @@ -3003,6 +3038,9 @@ static int cat_read(policydb_t * p goto bad; len = le32_to_cpu(buf[0]); + if(zero_or_saturated(len)) + goto bad; + catdatum->s.value = le32_to_cpu(buf[1]); catdatum->isalias = le32_to_cpu(buf[2]); @@ -3339,6 +3377,8 @@ static int filename_trans_rule_read(filename_trans_rule_t ** r, struct policy_fi return -1; len = le32_to_cpu(buf[0]); + if (zero_or_saturated(len)) + return -1; ftr->name = malloc(len + 1); if (!ftr->name) @@ -3580,6 +3620,8 @@ static int scope_read(policydb_t * p, int symnum, struct policy_file *fp) if (rc < 0) goto cleanup; key_len = le32_to_cpu(buf[0]); + if (zero_or_saturated(key_len)) + goto cleanup; key = malloc(key_len + 1); if (!key) goto cleanup; @@ -3664,8 +3706,8 @@ int policydb_read(policydb_t * p, struct policy_file *fp, unsigned verbose) } len = buf[1]; - if (len > POLICYDB_STRING_MAX_LENGTH) { - ERR(fp->handle, "policydb string length too long "); + if (len == 0 || len > POLICYDB_STRING_MAX_LENGTH) { + ERR(fp->handle, "policydb string length %s ", len ? "too long" : "zero"); return POLICYDB_ERROR; } @@ -3798,6 +3840,8 @@ int policydb_read(policydb_t * p, struct policy_file *fp, unsigned verbose) goto bad; } len = le32_to_cpu(buf[0]); + if (zero_or_saturated(len)) + goto bad; if ((p->name = malloc(len + 1)) == NULL) { goto bad; } @@ -3809,6 +3853,8 @@ int policydb_read(policydb_t * p, struct policy_file *fp, unsigned verbose) goto bad; } len = le32_to_cpu(buf[0]); + if (zero_or_saturated(len)) + goto bad; if ((p->version = malloc(len + 1)) == NULL) { goto bad; } diff --git a/libsepol/src/private.h b/libsepol/src/private.h index 9c700c9..0beb4d4 100644 --- a/libsepol/src/private.h +++ b/libsepol/src/private.h @@ -45,6 +45,9 @@ #define ARRAY_SIZE(x) (sizeof(x)/sizeof((x)[0])) +#define is_saturated(x) (x == (typeof(x))-1) +#define zero_or_saturated(x) ((x == 0) || is_saturated(x)) + /* Policy compatibility information. */ struct policydb_compat_info { unsigned int type;