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Code Issues Releases Activity

Fix up pointer issues with lib/libkvm

Browse Source 
In particular,
- avoid dereferencing NULL pointers
- test pointers against NULL, not 0
- test for errout == NULL in the top-level functions (kvm_open, kvm_openfiles,
  kvm_open2, etc)
- Replace a realloc and free on failure with reallocf

Found with: devel/cocchinelle

Differential Revision: https://reviews.freebsd.org/D5954
MFC after: 1 week
Reviewed by: jhb
Sponsored by: EMC / Isilon Storage Division
This commit is contained in:
Enji Cooper 2016-04-22 18:05:34 +00:00
parent 4c26ac696c
commit fb0e1892d9
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=298485
10 changed files with 52 additions and 35 deletions
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22
lib/libkvm/kvm.c
View File

@ -379,12 +379,12 @@ _kvm_open(kvm_t *kd, const char *uf, const char *mf, int flag, char *errout)
kd->vmfd = -1;
kd->pmfd = -1;
kd->nlfd = -1;
kd->vmst = 0;
kd->procbase = 0;
kd->argspc = 0;
kd->argv = 0;
kd->vmst = NULL;
kd->procbase = NULL;
kd->argspc = NULL;
kd->argv = NULL;
if (uf == 0)
if (uf == NULL)
uf = getbootfile();
else if (strlen(uf) >= MAXPATHLEN) {
_kvm_err(kd, kd->program, "exec file name too long");
@ -394,7 +394,7 @@ _kvm_open(kvm_t *kd, const char *uf, const char *mf, int flag, char *errout)
_kvm_err(kd, kd->program, "bad flags arg");
goto failed;
}
if (mf == 0)
if (mf == NULL)
mf = _PATH_MEM;
if ((kd->pmfd = open(mf, flag | O_CLOEXEC, 0)) < 0) {
@ -471,7 +471,7 @@ _kvm_open(kvm_t *kd, const char *uf, const char *mf, int flag, char *errout)
/*
* Copy out the error if doing sane error semantics.
*/
if (errout != 0)
if (errout != NULL)
strlcpy(errout, kd->errbuf, _POSIX2_LINE_MAX);
(void)kvm_close(kd);
return (0);
@ -484,7 +484,9 @@ kvm_openfiles(const char *uf, const char *mf, const char *sf __unused, int flag,
kvm_t *kd;
if ((kd = calloc(1, sizeof(*kd))) == NULL) {
(void)strlcpy(errout, strerror(errno), _POSIX2_LINE_MAX);
if (errout != NULL)
(void)strlcpy(errout, strerror(errno),
_POSIX2_LINE_MAX);
return (0);
}
return (_kvm_open(kd, uf, mf, flag, errout));
@ -513,7 +515,9 @@ kvm_open2(const char *uf, const char *mf, int flag, char *errout,
kvm_t *kd;
if ((kd = calloc(1, sizeof(*kd))) == NULL) {
(void)strlcpy(errout, strerror(errno), _POSIX2_LINE_MAX);
if (errout != NULL)
(void)strlcpy(errout, strerror(errno),
_POSIX2_LINE_MAX);
return (0);
}
kd->resolve_symbol = resolver;

8
lib/libkvm/kvm_amd64.c
View File

@ -118,7 +118,7 @@ _amd64_initvtop(kvm_t *kd)
amd64_pml4e_t *PML4;
kd->vmst = (struct vmstate *)_kvm_malloc(kd, sizeof(*kd->vmst));
if (kd->vmst == 0) {
if (kd->vmst == NULL) {
_kvm_err(kd, kd->program, "cannot allocate vm");
return (-1);
}
@ -153,6 +153,10 @@ _amd64_initvtop(kvm_t *kd)
}
pa = le64toh(pa);
PML4 = _kvm_malloc(kd, AMD64_PAGE_SIZE);
if (PML4 == NULL) {
_kvm_err(kd, kd->program, "cannot allocate PML4");
return (-1);
}
if (kvm_read2(kd, pa, PML4, AMD64_PAGE_SIZE) != AMD64_PAGE_SIZE) {
_kvm_err(kd, kd->program, "cannot read KPML4phys");
return (-1);
@ -188,7 +192,7 @@ _amd64_vatop(kvm_t *kd, kvaddr_t va, off_t *pa)
* If we are initializing (kernel page table descriptor pointer
* not yet set) then return pa == va to avoid infinite recursion.
*/
if (vm->PML4 == 0) {
if (vm->PML4 == NULL) {
s = _kvm_pa2off(kd, va, pa);
if (s == 0) {
_kvm_err(kd, kd->program,

6
lib/libkvm/kvm_arm.c
View File

@ -117,7 +117,7 @@ _arm_initvtop(kvm_t *kd)
}
vm = _kvm_malloc(kd, sizeof(*vm));
if (vm == 0) {
if (vm == NULL) {
_kvm_err(kd, kd->program, "cannot allocate vm");
return (-1);
}
@ -168,6 +168,10 @@ _arm_initvtop(kvm_t *kd)
return (-1);
}
l1pt = _kvm_malloc(kd, ARM_L1_TABLE_SIZE);
if (l1pt == NULL) {
_kvm_err(kd, kd->program, "cannot allocate l1pt");
return (-1);
}
if (kvm_read2(kd, pa, l1pt, ARM_L1_TABLE_SIZE) != ARM_L1_TABLE_SIZE) {
_kvm_err(kd, kd->program, "cannot read l1pt");
free(l1pt);

12
lib/libkvm/kvm_i386.c
View File

@ -162,6 +162,10 @@ _i386_initvtop(kvm_t *kd)
}
pa = le32toh(pa);
PTD = _kvm_malloc(kd, 4 * I386_PAGE_SIZE);
if (PTD == NULL) {
_kvm_err(kd, kd->program, "cannot allocate PTD");
return (-1);
}
for (i = 0; i < 4; i++) {
if (kvm_read2(kd, pa + (i * sizeof(pa64)), &pa64,
sizeof(pa64)) != sizeof(pa64)) {
@ -195,6 +199,10 @@ _i386_initvtop(kvm_t *kd)
}
pa = le32toh(pa);
PTD = _kvm_malloc(kd, I386_PAGE_SIZE);
if (PTD == NULL) {
_kvm_err(kd, kd->program, "cannot allocate PTD");
return (-1);
}
if (kvm_read2(kd, pa, PTD, I386_PAGE_SIZE) != I386_PAGE_SIZE) {
_kvm_err(kd, kd->program, "cannot read PTD");
return (-1);
@ -228,7 +236,7 @@ _i386_vatop(kvm_t *kd, kvaddr_t va, off_t *pa)
* If we are initializing (kernel page table descriptor pointer
* not yet set) then return pa == va to avoid infinite recursion.
*/
if (PTD == 0) {
if (PTD == NULL) {
s = _kvm_pa2off(kd, va, pa);
if (s == 0) {
_kvm_err(kd, kd->program,
@ -318,7 +326,7 @@ _i386_vatop_pae(kvm_t *kd, kvaddr_t va, off_t *pa)
* If we are initializing (kernel page table descriptor pointer
* not yet set) then return pa == va to avoid infinite recursion.
*/
if (PTD == 0) {
if (PTD == NULL) {
s = _kvm_pa2off(kd, va, pa);
if (s == 0) {
_kvm_err(kd, kd->program,

2
lib/libkvm/kvm_minidump_aarch64.c
View File

@ -81,7 +81,7 @@ _aarch64_minidump_initvtop(kvm_t *kd)
off_t off;
vmst = _kvm_malloc(kd, sizeof(*vmst));
if (vmst == 0) {
if (vmst == NULL) {
_kvm_err(kd, kd->program, "cannot allocate vm");
return (-1);
}

2
lib/libkvm/kvm_minidump_amd64.c
View File

@ -81,7 +81,7 @@ _amd64_minidump_initvtop(kvm_t *kd)
off_t off;
vmst = _kvm_malloc(kd, sizeof(*vmst));
if (vmst == 0) {
if (vmst == NULL) {
_kvm_err(kd, kd->program, "cannot allocate vm");
return (-1);
}

2
lib/libkvm/kvm_minidump_arm.c
View File

@ -84,7 +84,7 @@ _arm_minidump_initvtop(kvm_t *kd)
off_t off;
vmst = _kvm_malloc(kd, sizeof(*vmst));
if (vmst == 0) {
if (vmst == NULL) {
_kvm_err(kd, kd->program, "cannot allocate vm");
return (-1);
}

2
lib/libkvm/kvm_minidump_i386.c
View File

@ -81,7 +81,7 @@ _i386_minidump_initvtop(kvm_t *kd)
off_t off;
vmst = _kvm_malloc(kd, sizeof(*vmst));
if (vmst == 0) {
if (vmst == NULL) {
_kvm_err(kd, kd->program, "cannot allocate vm");
return (-1);
}

2
lib/libkvm/kvm_minidump_mips.c
View File

@ -89,7 +89,7 @@ _mips_minidump_initvtop(kvm_t *kd)
off_t off;
vmst = _kvm_malloc(kd, sizeof(*vmst));
if (vmst == 0) {
if (vmst == NULL) {
_kvm_err(kd, kd->program, "cannot allocate vm");
return (-1);
}

29
lib/libkvm/kvm_proc.c
View File

@ -544,7 +544,7 @@ kvm_getprocs(kvm_t *kd, int op, int arg, int *cnt)
size += size / 10;
kd->procbase = (struct kinfo_proc *)
_kvm_realloc(kd, kd->procbase, size);
if (kd->procbase == 0)
if (kd->procbase == NULL)
return (0);
osize = size;
st = sysctl(mib, temp_op == KERN_PROC_ALL ||
@ -614,7 +614,7 @@ kvm_getprocs(kvm_t *kd, int op, int arg, int *cnt)
}
size = nprocs * sizeof(struct kinfo_proc);
kd->procbase = (struct kinfo_proc *)_kvm_malloc(kd, size);
if (kd->procbase == 0)
if (kd->procbase == NULL)
return (0);
nprocs = kvm_deadprocs(kd, op, arg, nl[1].n_value,
@ -637,21 +637,19 @@ kvm_getprocs(kvm_t *kd, int op, int arg, int *cnt)
void
_kvm_freeprocs(kvm_t *kd)
{
if (kd->procbase) {
free(kd->procbase);
kd->procbase = 0;
}
free(kd->procbase);
kd->procbase = NULL;
}
void *
_kvm_realloc(kvm_t *kd, void *p, size_t n)
{
void *np = (void *)realloc(p, n);
void *np;
if (np == 0) {
free(p);
np = reallocf(p, n);
if (np == NULL)
_kvm_err(kd, kd->program, "out of memory");
}
return (np);
}
@ -672,7 +670,7 @@ kvm_argv(kvm_t *kd, const struct kinfo_proc *kp, int env, int nchr)
if (!ISALIVE(kd)) {
_kvm_err(kd, kd->program,
"cannot read user space from dead kernel");
return (0);
return (NULL);
}
if (nchr == 0 || nchr > ARG_MAX)
@ -681,7 +679,7 @@ kvm_argv(kvm_t *kd, const struct kinfo_proc *kp, int env, int nchr)
buf = malloc(nchr);
if (buf == NULL) {
_kvm_err(kd, kd->program, "cannot allocate memory");
return (0);
return (NULL);
}
buflen = nchr;
argc = 32;
@ -706,12 +704,11 @@ kvm_argv(kvm_t *kd, const struct kinfo_proc *kp, int env, int nchr)
* to the requested len.
*/
if (errno != ENOMEM || bufsz != (size_t)buflen)
return (0);
return (NULL);
buf[bufsz - 1] = '\0';
errno = 0;
} else if (bufsz == 0) {
return (0);
}
} else if (bufsz == 0)
return (NULL);
i = 0;
p = buf;
do {