| Message ID | 20200107144718.391550-1-danielhb413@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [1/1] 9p-local.c: always return -1 on error in local_unlinkat_common | expand |
I've changed "9p-local.c:" to "9p: local:" which is the usual prefix used for fsdev backend specific changes. On Tue, 7 Jan 2020 11:47:18 -0300 Daniel Henrique Barboza <danielhb413@gmail.com> wrote: > local_unlinkat_common() is supposed to always return -1 on error. > This is being done by jumps to the 'err_out' label, which is > a 'return ret' call, and 'ret' is initialized with -1. > > Unfortunately there is a condition in which the function will > return 0 on error: in a case where flags == AT_REMOVEDIR, 'ret' > will be 0 when reaching > > map_dirfd = openat_dir(...) > > And, if map_dirfd == -1 and errno != ENOENT, the existing 'err_out' > jump will execute 'return ret', when ret is still set to zero > at that point. > > This patch fixes it by changing all 'err_out' labels by > 'return -1' calls, ensuring that the function will always > return -1 on error conditions. 'ret' can be left unintialized > since it's now being used just to store the result of 'unlinkat' > calls. > > CC: Greg Kurz <groug@kaod.org> > Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com> > --- Applied to 9p-next. Thanks Daniel and feliz ano novo :) > hw/9pfs/9p-local.c | 14 ++++++-------- > 1 file changed, 6 insertions(+), 8 deletions(-) > > diff --git a/hw/9pfs/9p-local.c b/hw/9pfs/9p-local.c > index ca641390fb..de61aca216 100644 > --- a/hw/9pfs/9p-local.c > +++ b/hw/9pfs/9p-local.c > @@ -1076,7 +1076,7 @@ out: > static int local_unlinkat_common(FsContext *ctx, int dirfd, const char *name, > int flags) > { > - int ret = -1; > + int ret; > > if (ctx->export_flags & V9FS_SM_MAPPED_FILE) { > int map_dirfd; > @@ -1094,12 +1094,12 @@ static int local_unlinkat_common(FsContext *ctx, int dirfd, const char *name, > > fd = openat_dir(dirfd, name); > if (fd == -1) { > - goto err_out; > + return -1; > } > ret = unlinkat(fd, VIRTFS_META_DIR, AT_REMOVEDIR); > close_preserve_errno(fd); > if (ret < 0 && errno != ENOENT) { > - goto err_out; > + return -1; > } > } > map_dirfd = openat_dir(dirfd, VIRTFS_META_DIR); > @@ -1107,16 +1107,14 @@ static int local_unlinkat_common(FsContext *ctx, int dirfd, const char *name, > ret = unlinkat(map_dirfd, name, 0); > close_preserve_errno(map_dirfd); > if (ret < 0 && errno != ENOENT) { > - goto err_out; > + return -1; > } > } else if (errno != ENOENT) { > - goto err_out; > + return -1; > } > } > > - ret = unlinkat(dirfd, name, flags); > -err_out: > - return ret; > + return unlinkat(dirfd, name, flags); > } > > static int local_remove(FsContext *ctx, const char *path)
On 1/7/20 1:47 PM, Greg Kurz wrote: > I've changed "9p-local.c:" to "9p: local:" which is the usual prefix used for > fsdev backend specific changes. Good to know. Thanks for fixing it up. > > On Tue, 7 Jan 2020 11:47:18 -0300 > Daniel Henrique Barboza <danielhb413@gmail.com> wrote: > >> local_unlinkat_common() is supposed to always return -1 on error. >> This is being done by jumps to the 'err_out' label, which is >> a 'return ret' call, and 'ret' is initialized with -1. >> >> Unfortunately there is a condition in which the function will >> return 0 on error: in a case where flags == AT_REMOVEDIR, 'ret' >> will be 0 when reaching >> >> map_dirfd = openat_dir(...) >> >> And, if map_dirfd == -1 and errno != ENOENT, the existing 'err_out' >> jump will execute 'return ret', when ret is still set to zero >> at that point. >> >> This patch fixes it by changing all 'err_out' labels by >> 'return -1' calls, ensuring that the function will always >> return -1 on error conditions. 'ret' can be left unintialized >> since it's now being used just to store the result of 'unlinkat' >> calls. >> >> CC: Greg Kurz <groug@kaod.org> >> Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com> >> --- > > Applied to 9p-next. > > Thanks Daniel and feliz ano novo :) Bonne année! > >> hw/9pfs/9p-local.c | 14 ++++++-------- >> 1 file changed, 6 insertions(+), 8 deletions(-) >> >> diff --git a/hw/9pfs/9p-local.c b/hw/9pfs/9p-local.c >> index ca641390fb..de61aca216 100644 >> --- a/hw/9pfs/9p-local.c >> +++ b/hw/9pfs/9p-local.c >> @@ -1076,7 +1076,7 @@ out: >> static int local_unlinkat_common(FsContext *ctx, int dirfd, const char *name, >> int flags) >> { >> - int ret = -1; >> + int ret; >> >> if (ctx->export_flags & V9FS_SM_MAPPED_FILE) { >> int map_dirfd; >> @@ -1094,12 +1094,12 @@ static int local_unlinkat_common(FsContext *ctx, int dirfd, const char *name, >> >> fd = openat_dir(dirfd, name); >> if (fd == -1) { >> - goto err_out; >> + return -1; >> } >> ret = unlinkat(fd, VIRTFS_META_DIR, AT_REMOVEDIR); >> close_preserve_errno(fd); >> if (ret < 0 && errno != ENOENT) { >> - goto err_out; >> + return -1; >> } >> } >> map_dirfd = openat_dir(dirfd, VIRTFS_META_DIR); >> @@ -1107,16 +1107,14 @@ static int local_unlinkat_common(FsContext *ctx, int dirfd, const char *name, >> ret = unlinkat(map_dirfd, name, 0); >> close_preserve_errno(map_dirfd); >> if (ret < 0 && errno != ENOENT) { >> - goto err_out; >> + return -1; >> } >> } else if (errno != ENOENT) { >> - goto err_out; >> + return -1; >> } >> } >> >> - ret = unlinkat(dirfd, name, flags); >> -err_out: >> - return ret; >> + return unlinkat(dirfd, name, flags); >> } >> >> static int local_remove(FsContext *ctx, const char *path) >
diff --git a/hw/9pfs/9p-local.c b/hw/9pfs/9p-local.c index ca641390fb..de61aca216 100644 --- a/hw/9pfs/9p-local.c +++ b/hw/9pfs/9p-local.c @@ -1076,7 +1076,7 @@ out: static int local_unlinkat_common(FsContext *ctx, int dirfd, const char *name, int flags) { - int ret = -1; + int ret; if (ctx->export_flags & V9FS_SM_MAPPED_FILE) { int map_dirfd; @@ -1094,12 +1094,12 @@ static int local_unlinkat_common(FsContext *ctx, int dirfd, const char *name, fd = openat_dir(dirfd, name); if (fd == -1) { - goto err_out; + return -1; } ret = unlinkat(fd, VIRTFS_META_DIR, AT_REMOVEDIR); close_preserve_errno(fd); if (ret < 0 && errno != ENOENT) { - goto err_out; + return -1; } } map_dirfd = openat_dir(dirfd, VIRTFS_META_DIR); @@ -1107,16 +1107,14 @@ static int local_unlinkat_common(FsContext *ctx, int dirfd, const char *name, ret = unlinkat(map_dirfd, name, 0); close_preserve_errno(map_dirfd); if (ret < 0 && errno != ENOENT) { - goto err_out; + return -1; } } else if (errno != ENOENT) { - goto err_out; + return -1; } } - ret = unlinkat(dirfd, name, flags); -err_out: - return ret; + return unlinkat(dirfd, name, flags); } static int local_remove(FsContext *ctx, const char *path)
local_unlinkat_common() is supposed to always return -1 on error. This is being done by jumps to the 'err_out' label, which is a 'return ret' call, and 'ret' is initialized with -1. Unfortunately there is a condition in which the function will return 0 on error: in a case where flags == AT_REMOVEDIR, 'ret' will be 0 when reaching map_dirfd = openat_dir(...) And, if map_dirfd == -1 and errno != ENOENT, the existing 'err_out' jump will execute 'return ret', when ret is still set to zero at that point. This patch fixes it by changing all 'err_out' labels by 'return -1' calls, ensuring that the function will always return -1 on error conditions. 'ret' can be left unintialized since it's now being used just to store the result of 'unlinkat' calls. CC: Greg Kurz <groug@kaod.org> Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com> --- hw/9pfs/9p-local.c | 14 ++++++-------- 1 file changed, 6 insertions(+), 8 deletions(-)